A hot metal bar is submerged in a large reservoir of water whose temperature is 60°F. The temperature of the bar 20 s after submersion is 120°F. After 1 min submerged, the temperature has cooled to 100°F. A) Determine the cooling constant k.B) What is the differential equation satisfied by the temperature F(t) of the bar?C) What is the formula for F(t)?D) Determine the temperature of the bar at the moment it is submerged.

Answers

Answer 1

Answer:

A) cooling constant =  0.0101365

B) [tex]\frac{df}{dt} = k ( 60 - F )[/tex]

c)  F(t) = 60 + 77.46[tex]e^{0.0101365t}[/tex]

D)137.46 ⁰

Step-by-step explanation:

water temperature = 60⁰F

temperature of Bar after 20 seconds = 120⁰F

temperature of Bar after 60 seconds = 100⁰F

A) Determine the cooling constant K

The newton's law of cooling is given as

= [tex]\frac{df}{dt} = k(60 - F)[/tex]

= ∫ [tex]\frac{df}{dt}[/tex] = ∫ k(60 - F)

= ∫ [tex]\frac{df}{60 - F}[/tex] = ∫ kdt

= In (60 -F) = -kt - c

       60 - F = [tex]e^{-kt-c}[/tex]

      60 - F = [tex]C_{1} e^{-kt}[/tex]       ( note : [tex]e^{-c}[/tex] is a constant )

after 20 seconds

[tex]C_{1}e^{-k(20)}[/tex] = 60 - 120 = -60  

therefore [tex]C_{1} = \frac{-60}{e^{-20k} }[/tex] ------- equation 1

after 60 seconds

[tex]C_{1} e^{-k(60)}[/tex] = 60 - 100 = - 40  

therefore [tex]C_{1} = \frac{-40}{e^{-60k} }[/tex] -------- equation 2

solve equation 1 and equation 2 simultaneously

= [tex]\frac{-60}{e^{-20k} }[/tex] = [tex]\frac{-40}{e^{-60k} }[/tex]

= 6[tex]e^{20k}[/tex] = 4[tex]e^{60k}[/tex]

= [tex]\frac{6}{4} e^{40k}[/tex] = In(6/4) = 40k

cooling constant (k) = In(6/4) / 40 = 0.40546 / 40 = 0.0101365

B) what is the differential equation  satisfied

substituting the value of k into the newtons law of cooling)

60 - F = [tex]C_{1} e^{0.0101365(t)}[/tex]  

F(t) = 60 - [tex]C_{1} e^{0.0101365(t)}[/tex]

The differential equation that the temperature F(t) of the bar

[tex]\frac{df}{dt} = k ( 60 - F )[/tex]

C) The formula for F(t)

t = 20 , F = 120

F(t ) = 60 - [tex]C_{1} e^{0.0101365(t)}[/tex]

120 = 60 - [tex]C_{1} e^{0.0101365(t)}[/tex]

[tex]C_{1} e^{0.0101365(20)}[/tex] = 60

[tex]C_{1} = 60 * 1.291[/tex] = 77.46

C1 = - 77.46⁰ as the temperature is decreasing

The formula for f(t)

= F(t) = 60 + 77.46[tex]e^{0.0101365t}[/tex]

D) Temperature of the bar at the moment it is submerged

F(0) = 60 + 77.46[tex]e^{0.01013659(0)}[/tex]

F(0) = 60 + 77.46(1)

     = 137.46⁰


Related Questions

given the functions, f(x)=x^2 and g(x)=x+2, perform the indicated operation. when applicable, state the domain restriction. f(g(x)​

Answers

Answer:

h(g(x)) = x²+4x+4

Domain restriction = [tex][-\infty, \infty][/tex]

Step-by-step explanation:

Given the functions  h(x)=x^2 and g(x)=x+2, we are to find h(g(x)). To get the indicated operation we need to follow the steps;

Since the function in parenthesis g(x) = x+2

h(g(x)) can be written as h(x+2). Hence we are to look for the equivalent expression of  h(x+2).

Since h(x) = x², h(x+2) can simply be gotten by simply replacing the variable x in h(x) as x+2 as shown;

h(x+2) = (g(x))²

h(x+2) = (x+2)²

We can open the bracket

h(x+2) = x²+4x+4

The domain restriction is the point where the function cannot exist for the value of x. The function can therefore exist on any real value R. The only domain restriction is at the interval [tex][-\infty, \infty][/tex]

Hence h(g(x))  is equivalent to x²+4x+4.

Devaughn is 8 years older than Sydney. The sum of their ages is 64. What is Sydney's age?

Answers

Answer:

Sydney's age is 28

Step-by-step explanation:

Let Devaughn be D

And Sydney be S

D=S+8..... equation 1

D+S=64...... equation 2

Substitute equation 1 to equation 2

S+8+S=64

2S+8=64

2S=64-8

2S=56

S=56/2

S=28

Hope it helps

Good luck

Let’s take Sydney age as x
And Devaughn age as 8+x
Equation will be
8+x+x=64
8+2x=64
2x=64-8
2x=56
x=28
Therefore Sydney is 28years old

Tabitha wants to hang a painting in a gallery. The painting and frame must have an area of 58 square feet. The painting is 7 feet wide by 8 feet long. Which quadratic equation can be used to determine the thickness of the frame, x? (5 points)

Answers

Answer:

4x² + 30x - 2 = 0

Step-by-step explanation:

Given:

Area = 58 square feet

Width = 7 feet

Length = 8 feet

Since the area is 58, writing the equation, we have:

(8 + 2x)(7 + 2x) = 58

Now expand the equation:

56 + 16x + 14x + 4x² = 58

56 + 30x + 4x² = 58

Collect like terms:

30x + 4x² + 56 - 58 = 0

30x + 4x² - 2 = 0

Rearrange the equation to a proper quadratic equation:

4x² + 30x - 2 = 0

The quadratic equation that can be used to determine the thickness of the frame, x is 4x² + 30x - 2 = 0

Refer to the following wage breakdown for a garment factory:
Hourly Wages Number of employees
$4 up to $7 18
7 up to 10 36
10 up to 13 20
13 up to 16 6
What is the class interval for the preceding table of wages?
A. $4
B. $2
C. $5
D. $3

Answers

Answer:

The class interval is $3

Step-by-step explanation:

The class interval is simply the difference between the lower or upper class boundary or limit  of a class and the lower or upper class boundary or limit of the next class.

In this case for the class

$4 up to $7 18 and

$7 up to $10 36

The lower class boundary of the first class is $4 and the lower class boundary of the second class is $7

Hence the class interval = $7-$4= $3

A first number plus twice a second number is 14. Twice the first number plus the second totals 13. Find the numbers.

Answers

Answer: The first number is 4 and the second is 5

Step-by-step explanation:

Let's say the first number is x and the second is y:

x+2y=14

2x+y=13

I'll use the linear combination method to solve this.

  2x+4y=28

-  2x+y=13

3y=15

y = 5

x = 4

Hope it helps <3

Answer:

y=1

x=12

Step-by-step explanation:

Let the first number be x

Let the first number be y

Given:

x+2y=14

2x+y=13

Substitution:

x=14-2y

Solution:

2x+y=13

14-2y+y=13

-2y+y=13-14

-y=-1

y=1

x=14-2y

x=14-2(1)

x=14-2

x=12

Proof:

1) x+2y=14

12+2(1)=14

12+2=14

14=14

Hope this helps ;) ❤❤❤

Let me know if there is an error in my answer

Fred has $26 to buy sketch paper for his art class. Each sketch pad costs $4.
How many sketch pads can he buy? Do not include units in your answer.

Answers

Answer:

6 pads

Step-by-step explanation:

Take the amount of money and divide by the cost per pad

26/4 = 6 with 1 dollar left over

He can buy 6 pads

CAN ANYONE HELP ME PLEASE? Jen Butler has been pricing​ Speed-Pass train fares for a group trip to New York. Three adults and four children must pay $106. Two adults and three children must pay $75. Find the price of the​ adult's ticket and the price of a​ child's ticket.

Answers

Answer:

adult=18$ and children=13$

Step-by-step explanation:

a= adult. and. c= children

first change the statement into linear equation

3a+4c=106

2a+3c=75

then it just solving for a and y

3a+4c=106. a= 75-3c.

2

3(75-3c)+ 4c=106. solve for c

2

c=13

then find c by substituting the value you got into a . you can you either 3a+4c=106

or 2a+3c=75 to find the answer but the value of a is the same.

2a+3c=75. c=13

2a+3(13)=75

2a=75 -39

2a= 36

a=18

Answer:

Adults Ticket = $18

Child's Ticket = $13

Step-by-step explanation:

Let A denote the price of an adult's ticket

Let C denote the price of a child's ticket

It is given that the three adults and four children must pay $106.

Mathematically,

[tex]3A + 4C = 106 \:\:\:\:\:\:\:\:\:\:\: eq. 1[/tex]

It is also given that the two adults and three children must pay $75.

Mathematically,

[tex]2A + 3C = 75 \\\\2A = 75 - 3C[/tex]

[tex]$ A = \frac{(75 - 3C)}{2} \:\:\:\:\:\:\: eq\:. 2 $[/tex]

Substitute eq. 2 into eq. 1

[tex]3A + 4C = 106[/tex]

[tex]$ \frac{3(75 - 3C)}{2} + 4C = 106 $[/tex]

Simplify,

[tex]$ \frac{3(75 - 3C)}{2} + 4C = 106 $[/tex]

[tex]$ \frac{225 - 9C}{2} + 4C = 106 $[/tex]

[tex]$ \frac{225 - 9C + 2(4C)}{2} = 106 $[/tex]

[tex]$ \frac{225 - 9C + 8C}{2} = 106 $[/tex]

[tex]$ 225 - 9C + 8C = 2(106) $[/tex]

[tex]$ 225 - C = 212 $[/tex]

[tex]C = 225 - 212[/tex]

[tex]C = \$13[/tex]

Substitute the value of C into eq. 2

[tex]$ A = \frac{75 - 3(13)}{2} $[/tex]

[tex]$ A = \frac{75 - 39}{2} $[/tex]

[tex]A = \$18[/tex]

Therefore, the price of the​ adult's ticket is $18 and the price of a​ child's ticket is $13

In a random sample of 400 residents of Boston, 320 residents indicated that they voted for Obama in the last presidential election. Develop a 95% confidence interval estimate for the proportion of all Boston residents who voted for Obama.

Answers

Answer:

C.I =  0.7608   ≤ p ≤   0.8392

Step-by-step explanation:

Given that:

Let consider a  random sample n = 400 candidates where  320 residents indicated that they voted for Obama

probability [tex]\hat p = \dfrac{320}{400}[/tex]

= 0.8

Level of significance ∝ = 100 -95%

= 5%

= 0.05

The objective is to  develop a 95% confidence interval estimate for the proportion of all Boston residents who voted for Obama.

The confidence internal can be computed as:

[tex]=\hat p \pm Z_{\alpha/2} \sqrt{\dfrac{ p(1-p)}{n } }[/tex]

where;

[tex]Z_{0.05/2}[/tex] = [tex]Z_{0.025}[/tex] = 1.960

SO;

[tex]=0.8 \pm 1.960 \sqrt{\dfrac{ 0.8(1-0.8)}{400 } }[/tex]

[tex]=0.8 \pm 1.960 \sqrt{\dfrac{ 0.8(0.2)}{400 } }[/tex]

[tex]=0.8 \pm 1.960 \sqrt{\dfrac{ 0.16}{400 } }[/tex]

[tex]=0.8 \pm 1.960 \sqrt{4 \times 10^{-4}}[/tex]

[tex]=0.8 \pm 1.960 \times 0.02}[/tex]

[tex]=0.8 \pm 0.0392[/tex]

= 0.8 - 0.0392     OR   0.8 + 0.0392  

= 0.7608    OR    0.8392

Thus; C.I =  0.7608   ≤ p ≤   0.8392

Which of the following is not a solution to the inequality graphed below?

Answers

Answer:

C ( 1,-2)

Step-by-step explanation:

We can plot the points and see what point is not in the shaded section

help (6)(-1)(-3)(10)(-2)

Answers

Answer:

The answer is

- 360

Step-by-step explanation:

(6)(-1)(-3)(10)(-2)

Multiply the terms in the bracket

That's

(6)(-1) = - 6

(-3)(10) = - 30

So we have

(-6)(-30)(-2)

= 180( - 2)

= - 360

Hope this helps you

El precio de costo de “x” artículos es 60x + 4 000, además el precio de venta de los mismos es 80x. Determinar la cantidad de artículos que deben venderse si se quiere lograr una ganancia de S/. 12 000

Answers

Answer:

800 artículos.

Step-by-step explanation:

Sea x = la cantidad de artículos vendidos

De la pregunta,

Precio de costo = 60 x + 4000

Venta (precio de venta) = 80x

También nos dieron ganancias como S12000

Para determinar la ganancia

Precio de venta: precio de costo = beneficio (cuando el precio de venta es más alto que el precio de costo)

Por lo tanto,

12,000 = 80x - (60x + 4000)

12,000 = 80x - 60x - 4000

Recolectando términos similares

12,000 + 4,000 = 80x - 60x

16,000 = 20x

x = 16,000 / 20

x = 800

Por lo tanto, la cantidad de artículos que se venderán si desea obtener una ganancia de S12,000 es de 800 artículos.

At noon, ship A is 170 km west of ship B. Ship A is sailing east at 40 km/h and ship B is sailing north at 15 km/h. How fast is the distance between the ships changing at 4:00 PM

Answers

Answer:

The distance between the ships is changing at 42.720 kilometers per hour at 4:00 PM.

Step-by-step explanation:

Vectorially speaking, let assume that ship A is located at the origin and the relative distance of ship B with regard to ship A at noon is:

[tex]\vec r_{B/A} = \vec r_{B} - \vec r_{A}[/tex]

Where [tex]\vec r_{A}[/tex] and [tex]\vec r_{B}[/tex] are the distances of ships A and B with respect to origin.

By supposing that both ships are travelling at constant speed. The equations of absolute position are described below:

[tex]\vec r_{A} = \left[\left(40\,\frac{km}{h} \right)\cdot t\right]\cdot i[/tex]

[tex]\vec r_{B} = \left(170\,km\right)\cdot i +\left[\left(15\,\frac{km}{h} \right)\cdot t\right]\cdot j[/tex]

Then,

[tex]\vec r_{B/A} = (170\,km)\cdot i +\left[\left(15\,\frac{km}{h} \right)\cdot t\right]\cdot j-\left[\left(40\,\frac{km}{h} \right)\cdot t\right]\cdot i[/tex]

[tex]\vec r_{B/A} = \left[170\,km-\left(40\,\frac{km}{h} \right)\cdot t\right]\cdot i +\left[\left(15\,\frac{km}{h} \right)\cdot t\right]\cdot j[/tex]

The rate of change of the distance between the ship is constructed by deriving the previous expression:

[tex]\vec v_{B/A} = -\left(40\,\frac{km}{h} \right)\cdot i + \left(15\,\frac{km}{h} \right)\cdot j[/tex]

Its magnitude is determined by means of the Pythagorean Theorem:

[tex]\|\vec v_{B/A}\| = \sqrt{\left(-40\,\frac{km}{h} \right)^{2}+\left(15\,\frac{km}{h} \right)^{2}}[/tex]

[tex]\|\vec r_{B/A}\| \approx 42.720\,\frac{km}{h}[/tex]

The distance between the ships is changing at 42.720 kilometers per hour at 4:00 PM.

Imagine working in a freelance developer earning 80 USD per hour how many weeks you will have to take a 12 hour flight on a weekday you can either book a flight for ticket for 11 AM for 900 USD or 11 PM flight or 11 USD there is no Internet boards if you take the day off like you will lose a day of work what would you do

Answers

Answer:

pay the 11 AM ticket

Step-by-step explanation:

Note that the flight last for 12 hours, and assuming the freelance developer can still work (have access to the internet) on the airplane throughout the flight, he stand to earn $960 ($80*12), which will still cover the cost of the flight with a profit of $60 ($960-900).

However, if he decides to pay the $11 flight ticket and there is no Internet on boards; there by losing a day of work, he stand to have lost working time which would earn with $900.

Therefore, the best choice is to pay the 11 AM ticket.

11 ounces to 5 ounces

Answers

Answer: what is the question to this?

Step-by-step explanation: thanks let me know okay

Answer:

(11/5) (a ratio)

Step-by-step explanation:

11 ounces to 5 ounces could be rewritten as

 11 oz.

---------- = (11/5) (a ratio)

 5 oz

Identify the CONCLUSION of a hypothesis test of the following claim and sample data: Claim: "The average annual household income in Warren County is $47,500." A random sample of 86 households from this county is obtained, and they have an average annual income of $48,061 with a standard deviation of $2,351. Test the claim at the 0.02 significance level.

Answers

Complete Question

The options for the above question is  

a There is not sufficient evidence to warrant rejection of the claim.    

b  There is sufficient evidence to warrant rejection of the claim.

c There is sufficient evidence to support the claim.    

d There is not sufficient evidence to support the claim.

Answer:

Option A is correct

Step-by-step explanation:

From the question we are told that

     The  population mean is  [tex]\mu =[/tex]$47,500

     The sample size is [tex]n = 86[/tex]

      The sample  mean is  [tex]\= x =[/tex]$48,061

      The standard deviation is [tex]\sigma =[/tex]$2,351

       The  level of significance is  [tex]\alpha = 0.02[/tex]

The null hypothesis  is  

     [tex]H_o : \mu =[/tex]$47,500

 The  alternative hypothesis is

      [tex]H_a : \mu \ne[/tex] $47,500

The critical value of  [tex]\alpha[/tex] from the t-Distribution table is  [tex]Z_{\frac{\alpha }{2} } = 2.326[/tex]

Now the test statistics is mathematically evaluated as

       [tex]t = \frac{\= x - \mu }{ \frac{\sigma }{\sqrt{n} } }[/tex]

substituting values

      [tex]t = \frac{48061 - 47500 }{\frac{2351}{\sqrt{86} } }[/tex]

      [tex]t = 2.21[/tex]

Now from the values  obtained we can see that

        [tex]Z_{\frac{\alpha }{2} } > t[/tex]

hence we fail to reject the null hypothesis

Hence there is not sufficient evidence to warrant rejection of the claim

     

       

Farmers Jay, Peter, and Sam own rectangular farms, as indicated in the figure. Jay owns 2 acres of land, Peter owns 4 acres and Sam owns 6 acres. Find the area of the common pasture. PLEASE HELP ASAP!

Answers

Answer:

Area of the common pasture = 12 acres

Step-by-step explanation:

Let the dimensions of the farm owned by Jay are 'a' units and 'b' units.

Area of the farm = ab = 2 acres

Similarly, areas of the farm owned by Peter with dimensions 'a' unit and 'c' unit = ac = 4 acres

And area of the farm owned by Sam with dimensions 'b' and 'd' units = bd = 6 acres

Now, [tex]\frac{ab}{ac}=\frac{2}{4}[/tex]

[tex]\frac{b}{c}=\frac{1}{2}[/tex] ---------(1)

[tex]\frac{ab}{bd}=\frac{2}{6}[/tex]

[tex]\frac{a}{d}=\frac{1}{3}[/tex] ---------(2)

[tex]\frac{b}{c}\times \frac{a}{d}=\frac{1}{2}\times \frac{1}{3}[/tex]

[tex]\frac{ab}{cd}=\frac{1}{6}[/tex]

cd = 6(ab)

cd = 6 × 2 [Since ab = 2 acres]

    = 12 acres

Therefore, area of the common pasture will be 12 acres.

Can someone help me with this question

Answers

Answer:

Product of given question is 6√5

Step-by-step explanation:

Given:

3√2(√10)

Find:

Product.

Computation:

⇒ 3√2(√10)

⇒ 3√20

⇒ 3√4×5

⇒ 3√2×2×5

⇒ 3×2√5

⇒ 6√5

Product of given question is 6√5

Select the correct answer from each drop down menu.


The slope of diagonal OA is
A) 4/3
B) 3/4
C) 1
,and it’s equation is
A) 4x-y=0
B) x-3y=0
C) 4x-3y=0

Answers

Answer:

(A) [tex]\text{The slope of OA is }\dfrac{4}{3}[/tex]

(C) It’s equation is 4x-3y=0.

Step-by-step explanation:

Point O is at (0,0)

Point A is at (3,4)

[tex]\text{Slope of OA}=\dfrac{4-0}{3-0} \\m=\dfrac{4}{3}[/tex]

The equation of a straight line is in the form: y=mx+b

The y-intercept of the line OA=0

Therefore, we have:

[tex]y=\dfrac{4}{3}x+0\\3y=4x+0\\$Subtract 3y from both sides$\\4x-3y=0[/tex]

The equation of the line is: 4x-3y=0

Bubba Bulldog and all of his dog friends love to hide bones! Bubba hid 4 bones, Barry hid 5 bones, Larry hid 10 bones, and Goby hid 13 bones.
Find the mean number of dog bones.
_______dog bones

Answers

Answer:8

Step-by-step explanation:

You find the average which is adding them all together then dividing by how many numbers you added.

Help a man out, ive been stuck on this for a while.

Answers

Answer:

1. true - dilating figures does not change their angle measure

2. true - dilating figures does not change the orientation, so AD would still be on a horizontal line parallel to its current position

if sin theta = 2/3 which is possible

Answers

Answer:

C. cos theta = √5/3 and tan theta = 2/√5D. sec theta = 3/√5 and tan theta = 2/√5

Step-by-step explanation:

According to SOH in SOH, CAH TOA;

SOH means  sin theta = opposite/hypotenuse = 2/3

This shows that opposite = 2 and hypotenuse = 3. Before we can determine which of the expression is possible, we need to find the third side of the rigt angled triangle which is the adjacent.

According to Pythagoras theorem; hyp² = opp²+adj²

adj² = hyp² - opp²

adj² = 3² - 2²

adj² = 9 - 4

adj² = 5

adj = √5

Hence the adjacent side is √5.

From the trigonometry identity above;

cos theta = adj/hyp = √5/3 and tan theta = opp/adj = 2/√5

Since sec theta = 1/cos theta then sec theta = 1/(adj/hyp)

sec theta = hyp/adj = 3/√5

From the above calculation, the following are possible:

cos theta = √5/3, tan theta = 2/√5 and sec theta = 3/√5

The correct options are C and D

If one number is five more than another number, and the smaller number is half of the larger number, what are the two numbers?

Answers

Answer:

Larger number = 10Smaller number = 5

Step-by-step explanation:

Let larger number be x

Let smaller number be y

[tex]x = 5 + y[/tex]---> equation (i)

[tex]y = \frac{1}{2} x[/tex]

[tex]x = 2y[/tex]-----> equation (ii)

Equate equation (i) and (ii),

[tex]5 + y = 2y[/tex]

Move variable to L.H.S and change its sign:

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

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

[tex] - y = - 5[/tex]

The difference sign (-) will be cancelled on both sides

[tex]y = 5[/tex]

Putting the value of y in equation (ii) in order to find the value of X ( larger number)

[tex]x = 2y[/tex]

Plug the value of y

[tex] = 2 \times 5[/tex]

Calculate the product

[tex] = 10[/tex]

Hence,

Smaller number = 5

Larger number = 10

Hope this helps..

Best regards!!

Answer:

10 and 5

Step-by-step explanation:

Let the first number be x.

Let the second number be y.

x = 5 + y

y = 1/2x

Plug y as 1/2x in the first equation.

x = 5 + (1/2x)

Solve for x.

Subtract 1/2x on both sides.

x - 1/2x = 5 + 1/2x - 1/2x

1/2x = 5

Multiply both sides by 2.

2(1/2x) = 2(5)

x = 10

Plug x as 10 in the second equation.

y = 1/2(10)

Solve for y.

y = 5

x = 10

y = 5

The two numbers are 10 and 5.

10 is the larger number.

5 is the smaller number.

1/3 x =6 What would like match this answer

Answers

Answer:

x=18

Step-by-step explanation:

Answer:

x = 18

Step-by-step explanation:

Since 1/3x = 6,

x = 6 x 3

Thus, x = 18

how many solutions does this linear system hacve y=2/3x+2 6x-4y=-10

Answers

Answer:

the linear system has two valid solution.

Answer:one solution

Step-by-step explanation:

Determine whether the experiment is blind or double blind.Is the aspirin produced by World's Best Pharmaceutical Company better than that of a competitor at relieving headaches? 200 headache suffers are chosen at random. Migraned Testing Service administers the experiment and provides the results evaluation. Three levels are made: participants receive contents from Bottle A, Bottle B, or Bottle C. Other than the fact that one bottle contains placebo aspirin (but not which particular bottle contains placebo aspirin), no other information is given to the testing service regarding the bottles' contents.a. Blindb. Double blindc. Neither

Answers

Answer:

The correct answer is:

Double-blind (b)

Step-by-step explanation:

A blind/blinded experiment is one in which information which may influence the participant or experimenter is withheld throughout the process of the experiment either by masking (giving false identity) or completely blinded, to avoid biases that may arise from such knowledge by the participant or experimenter.

Blinding is of three types: single-blind, double-blind and triple-blind experiements and this is named with respect to three categories involved in the experiment; participant, researcher or a third party, which may include: analysts, monitoring committees stakeholders etc. The blinding type is explained as follows

Blinding Type              participant       researcher           Third-party

single-blind                   blinded               unblinded           unblinded

double-blind                  blinded               blinded               unblinded

triple-blind                     blinded               blinded                blinded

In this example, the 200 headache sufferers (participants) and the Migrane testing service (researchers) do not know the contents of the bottles being administered, whereas the pharmaceutical company (third-party knows), hence it is a double-blinded experiment.

Solve for X in the equation, where 4B = −2X − 2A

Answers

Answer:

X = [tex]\left[\begin{array}{ccc}2&-7&3\\13&0&2\end{array}\right][/tex]

Step-by-step explanation:

4B = -2X - 2A

Dividing both sides by -2

=> -2B = X + A

Subtracting A to both sides

=> X = -2B-A

Now, Let's Solve:

=> X = [tex]-2\left[\begin{array}{ccc}0&2&-2\\5&0&3\end{array}\right] -\left[\begin{array}{ccc}-2&3&1\\-3&0&4\end{array}\right][/tex]

=> X = [tex]\left[\begin{array}{ccc}-2*0&-2*2&-2*-2\\-2*5&-2*0&-2*3\end{array}\right] - \left[\begin{array}{ccc}-2&3&1\\-3&0&4\end{array}\right][/tex]

=> X = [tex]\left[\begin{array}{ccc}0&-4&4\\10&0&6\end{array}\right] - \left[\begin{array}{ccc}-2&3&1\\-3&0&4\end{array}\right][/tex]

=> X = [tex]\left[\begin{array}{ccc}0-(-2)&-4-3&4-1\\10-(-3)&0-0&6-4\end{array}\right][/tex]

=> X = [tex]\left[\begin{array}{ccc}2&-7&3\\13&0&2\end{array}\right][/tex]

Help! PLZ, 20 PTS in 10 mins if possible thx !!!! A gym charges $55 for a monthly membership and an additional $4.50 for each yoga class a member attends. Simba can spend at most $70 at the gym each month. Write an inequality that shows the maximum number of yoga classes, y, that Simba can attend while staying within his gym budget. _________

Answers

Answer:

(70-55)/4.5=y rounded down to the nearest whole number

Step-by-step explanation:

The first step is to take away the $55 from $70

70-55=15

Simba has $15 to spend on the yoga classes, to find the number of yoga classes she can attend, you divide 15 by the amount a yoga class costs, $4.50

15/4.50=3 1/3

Because she can not have 1/3 of a yoga class, she can attend 3 yoga classes in her budget.

Hope this helps, if you have any questions feel free to ask

Have a good day! :)

The following data values represent a sample. What is the variance of the
sample? X = 8. Use the information in the table to help you.
х
12
9
11
5
3
(x; - x)²
16
1
9
9
25

Answers

Answer:

The variance of the data is 15.

σ² = 15

Step-by-step explanation:

The mean is given as

X = 8

х        |    (x - X)    |    (x - X) ²

12       |        4         |    16

9        |        1         |     1    

11        |        3         |    9

5       |        -3        |    9

3       |        -5        |    25

The variance is given by

[tex]\sigma^2 = \frac{1}{n-1} \sum (x - X)^2[/tex]

[tex]\sigma^2 = \frac{1}{5 - 1} (16 + 1 + 9 + 9 +25) \\\\\sigma^2 = \frac{1}{4} ( 16 + 1 + 9 + 9 +25) \\\\\sigma^2 = \frac{1}{4} (60) \\\\\sigma^2 = 15[/tex]

Therefore, the variance of the data is 15.

what is this one i cant seem to figure it out

Answers

Answer:

73

Step-by-step explanation:

Since DA is the diameter, this means that you can divide the circle into two half-circles.  You will solve with the right half-circle.  A half-circle has a 180 total degrees.  Add up the values given and solve for x.

(2x) + (7x - 4) + (85) = 180

2x + 7x - 4 + 85 = 180

9x - 4 + 85 = 180

9x + 81 = 180

9x = 99

x = 11

Now that you have the value of x, solve for m∠CZB.

m∠CZB = 7x - 4

m∠CZB = 7(11) - 4

m∠CZB = 77 - 4

m∠CZB = 73

What is the y intercept of the function f(x)=2•3^x

Answers

Answer:

[tex]\boxed{Option \ A}[/tex]

Step-by-step explanation:

[tex]f(x) = 2*3^x[/tex]

y intercept is when x = 0

So, Putting x = 0 in the above function

=> f(0) = [tex]2*3^0[/tex]

=> f(0) = 2*1

=> f(0) = 2

So, y-intercept is (0,2)

Answer:

A

Step-by-step explanation:

f(x) = 2 × 3^x

Plug x as 0 to find y-intercept.

2 × 3⁰

2 × 1

= 2

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