ASAP!!! PLEASE help me with this question! I am really stuck...

ASAP!!! PLEASE Help Me With This Question! I Am Really Stuck...

Answers

Answer 1

Answer:

8π cm^2

Step-by-step explanation:

We proceed as follows;

To answer this question, what we need firstly is the name of the cross section that results from slicing a sphere into half.

The cross section that results is called a hemisphere, which is half the size of the sphere.

But before we can calculate the area of the new cross section, we will need the radius of the original shape.

This is obtainable from the volume of the shape.

Mathematically;

Volume of a sphere = 4/3 * π * r^3

32/3 * π = 4/3 * π * r^3

We can take off π/3 from both sides so we are left with;

32 = 4r^3

Divide through by 4

r^3 = 8

r is the cube root of 8 = 2 cm

Now we find the area of the hemisphere

Mathematically, the area of a hemisphere is 2 * π * r^2

using the value of r = 2 cm given above, we have Hemisphere area = 2 * π * 2^2 =8 π cm^2


Related Questions

why the system of si unit is developed​

Answers

Step-by-step explanation:

Hi, there!!!!

The main purpose of developing si unit is to have standard unit of measurements and to bring uniformity in whole world in terms of measurements.

I hope it helps you...

A box contains 6 red, 3 white, 2 green, and 1 black (total 12) identical balls. What is the least number of balls necessary to take out randomly (without looking) to be sure of getting at least two white balls?

Answers

Answer:

10

Step-by-step explanation:

12 total and 3 whites

there is 10 11 and 12.

f(x) = x^2 - 4x + 3 f(x) = 1/2x + p The system of equations above, when graphed in the xy-coordinate plane, intersects at the point (4, q). What is p?

Answers

Answer:

p = 1

Step-by-step explanation:

Given that the system intersect at (4, q) then this point satisfies both equations, that is

q = 4² - 4(4) + 3

q = [tex]\frac{1}{2}[/tex] (4) + p

Equating both gives

16 - 16 + 3 = 2 + p, that is

3 = 2 + p ( subtract 2 from both sides )

p = 1

Can you translate a mathematical expression into a verbal expression?

Answers

Step-by-step explanation:

An example of a mathematical expression with a variable is 2x + 3. All variables must have a coefficient, a number that is multiplied by the variable. In the expression 2x + 3, the coefficient of x is the number 2, and it means 2 times x plus 3. ... For example, 2x + 3 could also be expressed as 2(x) + 3 or 2 * x + 3. are you talking about this

find the value of x and y if the distance of the point (x,y) from (-2,0) and (2,0) are both 14 units.​

Answers

Answer:

[tex] (0, 8\sqrt{3}) [/tex]  and  [tex] (0, -8\sqrt{3}) [/tex] are both 14 units from points (-2, 0) and (2, 0).

Step-by-step explanation:

distance formula

[tex] d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2} [/tex]

We want the distance, d, from points (-2, 0) and (2, 0) to be 14.

Point (-2, 0):

[tex] 14 = \sqrt{(x - (-2))^2 + (y - 0)^2} [/tex]

[tex] \sqrt{(x + 2)^2 + y^2} = 14 [/tex]

Point (2, 0):

[tex] 14 = \sqrt{(x - 2)^2 + (y - 0)^2} [/tex]

[tex] \sqrt{(x - 2)^2 + y^2} = 14 [/tex]

We have a system of equations:

[tex] \sqrt{(x + 2)^2 + y^2} = 14 [/tex]

[tex] \sqrt{(x - 2)^2 + y^2} = 14 [/tex]

Since the right sides of both equations are equal, we set the left sides equal.

[tex] \sqrt{(x + 2)^2 + y^2} = \sqrt{(x - 2)^2 + y^2} [/tex]

Square both sides:

[tex] (x + 2)^2 + y^2 = (x - 2)^2 + y^2 [/tex]

Square the binomials and combine like terms.

[tex] x^2 + 4x + 4 + y^2 = x^2 - 4x + 4 + y^2 [/tex]

[tex] 4x = -4x [/tex]

[tex] 8x = 0 [/tex]

[tex] x = 0 [/tex]

Now we substitute x = 0 in the first equation of the system of equations:

[tex] \sqrt{(x + 2)^2 + y^2} = 14 [/tex]

[tex] \sqrt{(0 + 2)^2 + y^2} = 14 [/tex]

[tex] \sqrt{4 + y^2} = 14 [/tex]

Square both sides.

[tex] y^2 + 4 = 196 [/tex]

[tex] y^2 = 192 [/tex]

[tex] y = \pm \sqrt{192} [/tex]

[tex] y = \pm \sqrt{64 \times 3} [/tex]

[tex] y = \pm 8\sqrt{3} [/tex]

The points are:

[tex] (0, 8\sqrt{3}) [/tex]  and  [tex] (0, -8\sqrt{3}) [/tex]

I don't understand this question. Could someone please help me?

Answers

Answer:

its answer is a not b

As in Formula

A=3.14*r^2

A =144pift^2

Answer:

144π square feet

Step-by-step explanation:

The garden is shaped like a circle.

To find the area of it we can use the formula of area of a circle.

The formula for area of a circle is:

πr^2

Plug our values in.

π(12)^2

144π

The area of the garden is 144πft^2

Find the measure of one exterior angle in each regular polygon.

Answers

Answer:

72° and 45°

Step-by-step explanation:

The sum of the exterior angles of a polygon = 360°

Since the given polygons are regular, then

Pentagon (5 sides ) has

exterior angle = 360° ÷ 5 = 72°

Octagon ( 8 sides ) has

exterior angle = 360° ÷ 8 = 45°

Step-by-step explanation:

The exterior angle of a polygon is given by

360/n

where n is the number of sides

First figure

For the first shape it has five sides

That's it's a pentagon

The measure of one exterior angle of the shape is

360 / 5

= 72°

Second figure

For the second shape it has 8 sides that's it's an octagon

So the measure of one exterior angle of the shape is

360 / 8

= 45°

Hope this helps you

Samin can run 5 kilometers in 30 minutes. Assuming she keeps a constant pace, how many kilometers can she run in 45 minutes? URGENT ANSWERS PLEASE!

Answers

Answer:

7.5kilometer

Step-by-step explanation:

for 30mins semin runs 5kilometer

then for 1min: (1min×5kilometer)÷30mins,

therefore, for 45mins: (45mins×5kilometer)÷30mins=7.5kilometer

From the given information:

We are being informed that Samin can run for 5 kilometers in 30 minutes;

If Samin can run such a kilometer in 30 minutes;

5 kilometers = 30 minutes

In x kilometers = 45 minutes

By cross multiplying;

(x × 30 minutes) = 5 kilometers × 45 minutes

30x = 225 kilometer/minutes

[tex]x = \dfrac{225 \ kilometer/minutes}{30 minutes}[/tex]

[tex]\mathbf{x = 7.5 \ kilometers}[/tex]

Therefore, we can conclude that the Samin can run 7.5 kilometers in 45 minutes.

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A lead ball weighs 326 grams. Find the radius of the ball to the nearest tenth of a
centimeter.

Answers

Answer:

1.9cm

Step-by-step explanation:

The density d of a material is related to its mass m and volume V as follows;

d = [tex]\frac{m}{V}[/tex]             ------------------(i)

The material in question here is the lead ball.

Now, from known experiment;

the density of lead is 11.34g/cm³

From the question, the weight/mass of the lead ball is 326g

Substitute these values into equation (i) as follows;

11.34 = [tex]\frac{326}{V}[/tex]

V = [tex]\frac{326}{11.34}[/tex]

V = 28.75cm³

Now, since the ball is of course spherical, we can get the radius by using the following relation from the volume of a sphere;

V = [tex]\frac{4}{3} \pi r^3[/tex]          [V = volume, r = radius]

V = 28.75cm³

=> 28.75 = [tex]\frac{4}{3} \pi r^3[/tex]

=> 3 x 28.75 = 4 π r³

=> 86.25 = 4 π r³

=> 21.5625 = π r³      [Take π = 3.142]

=> 21.5625 = (3.142) r³      [divide both sides by 3.142]

=> 6.86 = r³              [Take the cube root of both sides]

=> ∛6.86 = ∛r³

=> 1.90 = r

Therefore, the radius is 1.9cm to the nearest tenth

Find the value.
X3-4 when x=3
PLEASE HELP!!! ASAP!!!

Answers

Answer:

23

Step-by-step explanation:

Raise 3 to the power of 3

27 - 4

Subtract 4 from 27

23

Hope this was correct

Answer:

23

Explanation:

step 1 - rewrite the expression with the value of x

[tex]x^3 - 4[/tex]

[tex](3)^3 - 4[/tex]

step 2 - solve the exponent

[tex](3)^3 - 4[/tex]

[tex]27 - 4[/tex]

step 3 - subtract

[tex]27 - 4[/tex]

[tex]23[/tex]

therefore, the value of the expression is 23.

Kelly is a waitress and her average tip rate is 18%. After taking a sample of her tips from a week, she thinks her tip rate is actually higher. The data below is the tip rate for 15 randomly chosen checks (the numbers represent percentage). Assume that tip rates are normally distributed.
18.5 18.2 20 21.3 17.9 17.9 18.1 17.5 20 18
a) Express the null and alternative hypotheses in symbolic form for this claim.
H0 : Select an answer
Ha: Select an answer
b) What is the test statistic. Round to 2 decimals.
c) What is the p-value. Round to 4 decimals p-value =

Answers

Answer:

Step-by-step explanation:

From the given information:

the null and alternative hypotheses in symbolic form for this claim can be computed as:

[tex]H_o:\mu = 18 \\ \\ H_a : \mu > 18[/tex]

Mean = [tex]\dfrac{18.5+18.2+20+21.3+17.9+17.9+18.1+17.5+20+18}{10}[/tex]

Mean = 18.74

Standard deviation  [tex]\sigma = \sqrt{\dfrac{\sum(x_i - \mu)^2}{N}}[/tex]

Standard deviation  [tex]\sigma = \sqrt{\dfrac{(18.5 - 18.74)^2+(18.2 - 18.74)^2+(20 - 18.74)^2+...+(18 - 18.74)^2}{10}}[/tex]

Standard deviation [tex]\sigma[/tex]   = 1.18

The test statistics can be computed as follows:

[tex]Z= \dfrac{X- \mu}{\dfrac{\sigma}{\sqrt{n}}}[/tex]

[tex]Z= \dfrac{18.6- 18}{\dfrac{1.18}{\sqrt{10}}}[/tex]

[tex]Z= \dfrac{0.6}{\dfrac{1.18}{3.162}}[/tex]

Z = 1.6078

Z = 1.61

Degree of freedom = n -1

Degree of freedom = 10 -1

Degree of freedom = 9

Using t - calculator at Z = 1.6078 and df = 9

The P - value = 0.0712

What type of linear system is shown below?
A inconsistent
B. consistent and independent
C. consistent and dependent
D. inconsistent and dependent

Graph is attached , please help

Answers

Answer:

The linear system shown on the graph is consistent and independent

Step-by-step explanation:

The linear system shown on the graph is consistent because it has at least one solution which satisfy both linear graphs. The solution is at the point of interception of the two line graphs.

The linear system shown on the graph is independent because the two line graphs are distinct and not parallel or dependent on one another.

Therefore, The linear system shown on the graph is consistent and independent

Solve the inequality.

9p+23<41

Answers

Answer:

p < 2

Step-by-step explanation:

9p + 23 < 41

p < 2

Answer:

p < 2

Step-by-step explanation:

9p + 23 < 41

9p < 18

p < 2

4^6 • 4^-8 pls answer

Answers

Answer:

[tex]\boxed{4^{-2}}[/tex]

Step-by-step explanation:

[tex]4^6 \times 4^{-8}[/tex]

When bases are same for exponents and it is multiplication, then add the exponents.

[tex]4^{6+-8}[/tex]

[tex]4^{-2}[/tex]

Explanation: Since these two powers have the same base of 4, you can multiply them together by simply adding their exponents to get 4⁻².

When applying your exponent rules, the bases don't change!

A point H is 20m away from the foot of a tower on the same horizontal ground. From the point H, the angle of elevation of the point (P) on the tower and the top(T) of the tower are 30° and 50° respectively.
( a) draw a diagram to illustrate the information above.
(b) calculate correct to 3 s.f,
( I) /PT/
(ii) the distance between H and the too of the tower.
(III) the position of H if the angle of depression of H from the too of the tower is to be 40°

Answers

Answer:

a. See Attachment 1

b. [tex]PT = 12.3\ m[/tex]

c. [tex]HT = 31.1\ m[/tex]

d. [tex]OH = 28.4\ m[/tex]

Step-by-step explanation:

Calculating PT

To calculate PT, we need to get distance OT and OP

Calculating OT;

We have to consider angle 50, distance OH and distance OT

The relationship between these parameters is;

[tex]tan50 = \frac{OT}{20}[/tex]

Multiply both sides by 20

[tex]20 * tan50 = \frac{OT}{20} * 20[/tex]

[tex]20 * tan50 = OT[/tex]

[tex]20 * 1.1918 = OT[/tex]

[tex]23.836 = OT[/tex]

[tex]OT = 23.836[/tex]

Calculating OP;

We have to consider angle 30, distance OH and distance OP

The relationship between these parameters is;

[tex]tan30 = \frac{OP}{20}[/tex]

Multiply both sides by 20

[tex]20 * tan30 = \frac{OP}{20} * 20[/tex]

[tex]20 * tan30 = OP[/tex]

[tex]20 * 0.5774= OP[/tex]

[tex]11.548 = OP[/tex]

[tex]OP = 11.548[/tex]

[tex]PT = OT - OP[/tex]

[tex]PT = 23.836 - 11.548[/tex]

[tex]PT = 12.288[/tex]

[tex]PT = 12.3\ m[/tex] (Approximated)

--------------------------------------------------------

Calculating the distance between H and the top of the tower

This is represented by HT

HT can be calculated using Pythagoras theorem

[tex]HT^2 = OT^2 + OH^2[/tex]

Substitute 20 for OH and [tex]OT = 23.836[/tex]

[tex]HT^2 = 20^2 + 23.836^2[/tex]

[tex]HT^2 = 400 + 568.154896[/tex]

[tex]HT^2 = 968.154896[/tex]

Take Square Root of both sides

[tex]HT = \sqrt{968.154896}[/tex]

[tex]HT = 31.1\ m[/tex] (Approximated)

--------------------------------------------------------

Calculating the position of H

This is represented by OH

See Attachment 2

We have to consider angle 50, distance OH and distance OT

The relationship between these parameters is;

[tex]tan50 = \frac{OH}{OT}[/tex]

Multiply both sides by OT

[tex]OT * tan50 = \frac{OH}{OT} * OT[/tex]

[tex]OT * tan50 = {OH[/tex]

[tex]OT * 1.1918 = OH[/tex]

Substitute [tex]OT = 23.836[/tex]

[tex]23.836 * 1.1918 = OH[/tex]

[tex]28.4= OH[/tex]

[tex]OH = 28.4\ m[/tex] (Approximated)

Please can someone help

Answers

Answer:

a) 0

b) 1

c) 0

Step-by-step explanation:

These are common values from the unit circle but you could also just check with your calculator. Just be sure to set it to degree mode and not radian mode.

Which of the following sets contains all roots of the polynomial f(x)=2x^3+3x^2-3x-2?

Answers

Answer:

C

Step-by-step explanation:

Given

f(x) = 2x³ + 3x² - 3x - 2

Note that

f(1) = 2 + 3 - 3 - 2 = 0 , thus

(x - 1) is a factor

Dividing f(x) by (x - 1) gives

f(x) = (x - 1)(2x² + 5x + 2) = (x - 1)(x + 2)(2x + 1)

To find the roots equate f(x) to zero, that is

(x - 1)(x + 2)(2x + 1) = 0

Equate each factor to zero and solve for x

x - 1 = 0 ⇒ x = 1

x + 2 = 0 ⇒ x = - 2

2x + 1 = 0 ⇒ 2x = - 1 ⇒ x = - [tex]\frac{1}{2}[/tex]

The solution set is therefore

{ - 2, - [tex]\frac{1}{2}[/tex], 1 } → C

One liter of paint is needed to cover all 6 sides of a cubical block. How many liters will be needed to cover all 6 sides of a second cubical block whose edge is twice as long as an edge on the first block?

Will mark brainlist

Answers

Answer:

4 liters

Step-by-step explanation:

Let's assume that the side lengths of the cubical block are 2 inches.

This means that one of the sides area is 4 in².

Multiplying this by 6 (for there are 6 sides) gets us 24 in².

So one liter of paint covers 24 in².

Now if the side lengths (edge) of the second block is doubled, that means that the side lengths are [tex]2\cdot2 = 4[/tex] inches.

So the area of one side is 16 in².

Multiplying this by 6 (as there are 6 sides) gets us 96 in².

To find how many liters of paint this will take, we divide 96 by 24.

[tex]96\div24=4[/tex]

So 4 liters of paint will be needed for the second cubical block.

Hope this helped!

In a certain group of students, the probability of a randomly-chosen student being male is 40%, the probability of the student studying Spanish is 18%, and the probability of the student being a male who studies Spanish is 5%. What’s the probability of the student being a male, if you know the student studies Spanish

Answers

Answer:

27.8%

Step-by-step explanation:

P(male | Spanish) = P(male and Spanish) / P(Spanish)

P(male | Spanish) = 0.05 / 0.18

P(male | Spanish) = 0.278

The probability of the student being a male is 27.8%

What is probability?

Probability is defined as the ratio of the number of favorable outcomes to the total number of outcomes in other words the probability is the number that shows the happening of the event.

Probability = Number of favorable outcomes / Number of sample

Given that in a certain group of students, the probability of a randomly-chosen student being male is 40%, the probability of the student studying Spanish is 18%, and the probability of the student being a male who studies Spanish is 5%.

The probability of the student being a male will be calculated as below:-

P(male | Spanish) = P(male and Spanish) / P(Spanish)

P(male | Spanish) = 0.05 / 0.18

P(male | Spanish) = 0.278

Therefore, the probability of the student being a male is 27.8%

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Help it’s urgent please

Answers

Answer:

[tex] \frac{5 {x}^{2} + 20xy + 20 {y}^{2} }{x ^{2} - xy - {6y}^{2} } [/tex]

To simplify first factorize both the numerator and the denominator

For the numerator

5x² + 20xy + 20y²

Factor 5 out

5 ( x² + 4xy + 4y²)

Using a² + 2ab + b² = ( a + b)²

The numerator is

5( x + 2y)²

For the denominator

x² - xy - 6y²

Rewrite -xy as a difference

x² + 2xy - 3xy - 6y²

Factorize

We have the denominator as

( x + 2y)( x - 3y)

So we now have

[tex] \frac{5(x + 2y)(x + 2y)}{(x + 2y)(x - 3y)} [/tex]

Simplify

[tex] \frac{5(x + 2y)}{x - 3y} [/tex]

We have the final answer as

[tex] \frac{5x + 10y}{x - 3y} [/tex]

Hope this helps you

Please help Asap!!!Math question

Answers

Answer:

first one

Step-by-step explanation:

Find the midpoint of the segment between the points (−5,13) and (6,4)

Answers

Answer:

(0.5, 8.5)

Step-by-step explanation:

use this formula ((x1+x2/2), (y1+y2/2)) if you use desmos graphing calculator and you type this formula in, all you have to do it put in the correct numbers and you get your midpoint.

Hope this helped :)

The midpoint of the segment between the points (−5,13) and (6,4) are (0.5 and 8.5)

We have given that, the points (−5,13) and (6,4)

We have to determine the midpoints

What is the formula for the midpoint?

((x1+x2/2), (y1+y2/2))

x1=-5,x2=6,y1=13 and y2=4

-5+6/2=1/2=0.5

and next is,

13+4/2=17/2=8.5

The midpoint of the segment between the points (−5,13) and (6,4) are (0.5 and 8.5)

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Explain how to sketch a graph of the function f(x) = x3 + 2x2 – 8x. Be sure to include end-behavior, zeroes, and intervals where the function is positive and negative.

Answers

Answer:

Step-by-step explanation:

First, for end behavior, the highest power of x is x^3 and it is positive. So towards infinity, the graph will be positive, and towards negative infinity the graph will be negative (because this is a cubic graph)

To find the zeros, you set the equation equal to 0 and solve for x

x^3+2x^2-8x=0

x(x^2+2x-8)=0

x(x+4)(x-2)=0

x=0   x=-4   x=2

So the zeros are at 0, -4, and 2. Therefore, you can plot the points (0,0), (-4,0) and (2,0)

And we can plug values into the original that are between each of the zeros to see which intervals are positive or negative.

Plugging in a -5 gets us -35

-1 gets us 9

1 gets us -5

3 gets us 21

So now you know end behavior, zeroes, and signs of intervals

Hope this helps

The zeroes of the function are -4, 0 and 2.

The intervals where the function is positive is [tex]-4 < x < 2, \ \ x >2[/tex].

The intervals where the function is negative is [tex]x < -4[/tex].

The given parameters:

f(x) = x³ + 2x² - 8x

What is zeroes of a function?

The zeroes of a function is the possible values of the unknown that makes the entire function to be zero.

The zeroes of the cubic equation is calculated as follows;

f(x) = 0

x³ + 2x² - 8x

factorize as follows;

[tex]x(x^2 + 2x -8) = 0\\\\x(x^2 + 4x - 2x -8) = 0\\\\x[x (x + 4 )-2(x + 4)]= 0\\\\x(x + 4)(x -2)=0\\\\x = 0, \ \ x = -4 \ \ x = 2[/tex]

The intervals where the function is positive and negative is determined as follows;

[tex]x(x + 4) (x - 2)\\\\[/tex]

[tex]when, \ x = -5, \ f(x) = -ve\\\\when, \ x = -4, \ f(x) =0\\\\when , \ x = -3, \ f(x) = +ve[/tex]

The intervals where the function is positive is determined as;

[tex]-4 < x < 2, \ \ x >2[/tex]

The intervals where the function is negative is determined as;

[tex]x < -4[/tex]

Learn more about graph of cubic equation here: https://brainly.com/question/8878887

Which of the following Functions is NOT Linear? A:f(x)=x+0.5 B:F(x)=-x+0.5 C: F(x)=x^2-0.5 D: f(x)=0.5x

Answers

Answer:

C: F(x)=x^2-0.5

Step-by-step explanation:

When the x is squared it's a parabola. A linear graph is shaped like a straight line, while a parabola is curved inward. I have included a graph of what that function would look like (tap/click on it to see the full graph.)

Answer:

C: f(x) = x² - 0.5

Step-by-step explanation:

The grsaph of the linear function is a straight line.

The equation of a line in the slope-intercept fomr is:

y = mx + b

where

m - slope

b - y-intercept

We have:

A: f(x) = x + 0.5

it's a linear function: m = 1, b = 0.5

B: f(x) = -x + 0.5

it's a linear function: m = -1, b = 0.5

C: f(x) = x² - 0.5

it's not a linear function because in the equation is square of x (x²).

The graph of this function is a parabola.

D: f(x) = 0.5x

it's a linear function: m = 0.5, b = 0

The logistic growth function ​f(t)equals440 Over 1 plus 13.7 e Superscript negative 0.28 t EndFraction describes the population of a species of butterflies t months after they are introduced to a​ non-threatening habitat. How many butterflies are expected in the habitat after 20 ​months? Round to nearest whole number.

Answers

Answer:

8685 butterflies

Step-by-step explanation:

Given the logistics growth function expressed as ​f(t)equals440 Over 1 plus 13.7 e Superscript negative 0.28 t which describes the population of a species of butterflies t months after they are introduced to a​ non threatening habitat, to know the number of butterflies expected butterflies are expected in the habitat after 20 ​months, we will substitute t = 20 into the function.

f(20) = 440/1+13.7exp-(0.28×20)

f(20) = 440/1+13.7exp-(5.60)

f(20) = 440/1+(13.7× 0.003698)

f(20) = 440/1+0.05066

f(20) = 440/1.05066

f(20) = 8684.9

This means there will be approximately 8685 butterflies in the habitat after 20months.

Para ingresar a la Universidad del Chocó se aplica una prueba de razonamiento que consta de 30 preguntas. Por cada respuesta correcta se asignan 5 puntos y por cada incorrecta (o no contestada) se restan 2 puntos. Si un participante obtuvo un puntaje de 94 puntos, ¿cuántas preguntas

Answers

Complete question:

Para ingresar a la Universidad del Chocó se aplica una prueba de razonamiento que consta de 30 preguntas. Por cada respuesta correcta se asignan 5 puntos y por cada incorrecta (o no contestada) se restan 2 puntos. Si un participante obtuvo un puntaje de 94 puntos, ¿cuantas preguntas respondió bien?

Responder:

número de respuestas correctas = 22

Explicación paso a paso:

Dado lo siguiente:

Número total de preguntas = 30

Deje respuestas correctas = y; Respuestas incorrectas = n

Marca otorgada por y = 5

Marca deducida por n = 2

Si el total de preguntas = 30; luego

y + n = 30 - - - - (1)

Puntuación total obtenida = 94; luego

5y - 2n = 94 - - - (2)

De 1),

y + n = 30

y = 30 - n

Sustituya y = 30 - n en equ (2)

5 (30 - n) - 2n = 94

150 - 5n - 2n = 94

150 - 7n = 94

-7n = 94-150

-7n = - 56

n = 56/7

n = 8

Sustituir n = 8 en (1)

y + n = 30

y + 8 = 30

y = 30 - 8

y = 22

y = número de respuestas correctas = 22

n = número de respuestas incorrectas = 8

Usando un sistema de ecuaciones, se encuentra que el participante obtuve 22 respuestas correctas.

En el sistema, x es el número de respuestas correctas, con y siendo el número de respuestas incorrectas.

Total de 30 preguntas, o sea:

[tex]x + y = 30 \rightarrow y = 30 - x[/tex]

5 puntos asignados por cada respuesta correcta, 2 restados por cada respuesta incorrecta. Puntaje de 94 puntos, o sea:

[tex]5x - 2y = 94[/tex]

Considerando [tex]y = 30 - x[/tex]

[tex]5x - 60 + 2x = 94[/tex]

[tex]7x = 154[/tex]

[tex]x = \frac{154}{7}[/tex]

[tex]x = 22[/tex]

El participante obtuve 22 respuestas correctas.

Un problema similar es dado en https://brainly.com/question/24646137

Simplify the polynomial expressions by combining like terms, and then multiply the resulting
binomial expressions to find their product.
(6x - 9 - 2x)(8 + 5x - 5)​

Answers

Answer:

The simplified expression is

20x^2 - 33x - 27

Step-by-step explanation:

(6x - 9 - 2x)(8 + 5x - 5)​

We must first rewrite the expression as a product of two binomials.

This can be done by adding like terms

(6x - 9 - 2x)(8 + 5x - 5)​

We have,

(4x-9)(5x+3)

Multiplying the resulting binomial expression

(4x-9)(5x+3)

(20x^2+12x-45x-27)

Add the like terms

20x^2-33x-27

The simplified expression is

20x^2 - 33x - 27

Twenty x squared minus thirty-three x minus twenty-seven

Answer:

20x^2 - 33x - 27

Step-by-step explanation:

The length of a rectangle is 7 meters longer than its width. What is the width of this rectangle if its perimeter is equal to 86 meters?

Answers

Answer:

18 meters

Step-by-step explanation:

If the width is w, the length is w + 7.

Perimeter = 2(width + length), therefore:

86 = 2(w + w + 7)

86 = 2(2w + 7)

43 = 2w + 7

36 = 2w

w = 18

Answer:

18 meters

Step-by-step explanation:

Given,

Let length of a rectangle be ' x + 7 ' meters

Let width of a rectangle be ' x ' meters

Perimeter = 86 meters

Now, let's find the width of the rectangle:

Perimeter of rectangle = [tex]2(l + b)[/tex]

plug the values

[tex]86 = 2(x + 7 + x)[/tex]

Collect like terms

[tex]86 = 2(2x + 7)[/tex]

Distribute 2 through the parentheses

[tex]86 = 4x + 14[/tex]

Move constant to R.H.S and change its sign

[tex]86 - 14 = 4x[/tex]

Calculate the difference

[tex]72 = 4x[/tex]

Swipe the sides of the equation

[tex]4x = 72[/tex]

Divide both sides of the equation by 4

[tex] \frac{4x}{4} = \frac{72}{4} [/tex]

Calculate

[tex]x = 18[/tex] meters

Hope this helps..

Best regards!!

Jack had 4 hours of school. He spent 45 minutes in the library and 12 hour on a science lecture and had a lunch break of 25 minutes. How much time is left for the school to get over? (Write the answer as a fraction.)

Answers

Answer:

[tex]\dfrac{10}{4} \ hour[/tex]

Step-by-step explanation:

Given that :

Jack had 4 hours of school.

He spent 45 minutes in the library

1/2 hour on a science lecture  and;

had a lunch break of 25 minutes

The objective is to determine how much time is left for the school to get over and we are to write the answer as a fraction.

In order to do that, we will have to convert the minutes into hours,

we all know that; 60 minutes = 1 hour.

Then,

45 minutes = (45/60)hour = 3/4 hour

25/60 minutes = 1/4 hour

Therefore, the amount of time left  for the school to get over is:

= [tex]4 - (\dfrac{3}{4}+\dfrac{1}{2}+ \dfrac{1}{4})[/tex]

=  [tex]\dfrac{16-(3+2+1)}{4}[/tex]

= [tex]\dfrac{16-6}{4}[/tex]

= [tex]\dfrac{10}{4} \ hour[/tex]

Pam works as an office administrator. She spends $7500 of her income on personal expenses each year. If this represents 18% of her salary, how much money does Pam earn in one year? Round your answer to the nearest whole dollar.

Answers

Answer:

Her annual salary is approximately $41,667

Step-by-step explanation:

Hello,

This question deals with percentage of a number and it's very easy :)

First of all, get the data and understand what's required of us.

Pam spends $7500 yearly on expenses

But this amount represents 18% of her annual income.

Let her annual income be represented by x

18% = 7500 / x

18÷100 = 7500÷x

cross multiply and solve for x

18 × x = 7500 × 100

18x = 750,000

divide both sides by 18

18x / 18 = 750,000 / 18

x = $41,666.67

x = $41,667

Her annual salary is approximately $41,667

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