Let A(t) denote the amount of salt (in kg) in the tank at time t.
At the start, there are 80 kg of salt in the tank, so A(0) = 80.
Solution flows into the tank at a rate of 8 L/min at a concentration of 0.04 kg/L, so that salt flows in at a rate of
(8 L/min) * (0.04 kg/L) = 0.32 kg/min
Solution flows out at the same rate, but its concentration depends on the amount of salt in the tank. The concentration of the solution is the proportion of salt in the liquid to the total volume of the liquid. Solution flows in and out at 8 L/min, so the volume of liquid (1000 L) stays the same. A(t) is the amount of salt in the tank, so the concentration is A(t)/1000 kg/L. Hence salt flows out at a rate of
(8 L/min) * (A(t)/1000 kg/L) = 0.008 A(t) kg/min
The net rate at which salt flows through the system is then given by the differential equation,
dA(t)/dt = 0.32 - 0.008 A(t)
(Don't forget to include the initial condition)
The floor of a shed given on the right has an area of 44 square feet . The floor is in the shape of a rectangle whose length is 3 less than twice the width. Find the length and width of the floor of the shed.
Answer:
The length and width of the floor of the shed are 8 feet and 5.5 feet, respectively.
Step-by-step explanation:
Given that the shape of the shed is a rectangle, the expression for the area is:
[tex]A = w \cdot l[/tex]
Where [tex]w[/tex] and [tex]l[/tex] are the width and length of the shed, measured in feet. In addition, the statement shows that [tex]l = 2\cdot w - 3\,ft[/tex]. Then, the equation of area is expanded by replacing length:
[tex]A = w\cdot (2\cdot w - 3)[/tex]
[tex]A = 2\cdot w^{2} - 3\cdot w[/tex]
If [tex]A = 44\,ft^{2}[/tex], then, a second-order polynomial is formed:
[tex]2\cdot w^{2}-3\cdot w - 44 = 0[/tex]
The roots of this equation are found via General Equation for Second-Order Polynomials:
[tex]w_{1} = \frac{11}{2}\,ft[/tex] and [tex]w_{2} = -4\,ft[/tex]
Only the first roots is a physically reasonable solution. Then, the length of the shed is:
[tex]l = 2\cdot \left(\frac{11}{2}\,ft \right)-3\,ft[/tex]
[tex]l = 8\,ft[/tex]
The length and width of the floor of the shed are 8 feet and 5.5 feet, respectively.
6th grade math, help me please.
Answer:
a) [tex]\frac{2}{3} \,\frac{lb}{bread}[/tex]
b) [tex]1\frac{1}{4} \,\frac{in}{domino}[/tex]
Step-by-step explanation:
Part a:
every 4 lbs of flour, she makes 6 loaves of bread. this as a rate in simplest fraction form is:
[tex]\frac{4}{6} \,\frac{lb}{bread} = \frac{2}{3} \,\frac{lb}{bread}[/tex]
Part b:
every 10 inches , 8 dominoes can be placed. then the rate can be written as:
[tex]\frac{10}{8} \,\frac{in}{domino} = \frac{5}{4} \,\frac{in}{domino} =1\frac{1}{4} \,\frac{in}{domino}[/tex]
Use a graphing calculator to sketch the graph of the quadratic equation and then give the coordinates for the x-intercepts (if they exist) y=x2+7x+10 A (-2,0),(5,0) B (2,0);(-5,0) C (2,0);(5,0) D (-2,0);(-5,0)
Answer:
Option D.
Step-by-step explanation:
The given quadratic equation is
[tex]y=x^2+7x+10[/tex]
We need to draw the graph of given equation by using graphing calculator as shown below.
From the graph it is clear that the parabola intersect the x-axis at points (-2,0) and (-5,0). So, the x-intercepts are (-2,0) and (-5,0).
Therefore, the correct option is D.
Below are some of the scores on a math quiz given last week,
{82, 73, 74, 78, 46, 73}
What will happen to the mean of the quiz scores if the outlier is removed?
A
The mean will decrease.
OB
The mean will increase
C
There is not enough information given.
OD
The mean will not change.
Answer:
B: The mean will increase
Step-by-step explanation: The outlier is 46, which is way below all the other numbers, which is the definition of an outlier. If we remove a really low number from the set, then the mean(average) will increase.
|x–5|=|x+5| If you answer this question before 2:35 pm on July 28, 2020, I will give 10 points!!
Answer:
[tex]\boxed{x=0}[/tex]
Step-by-step explanation:
[tex]|x-5|=|x+5|[/tex]
Solve absolute value.
There are two possibilities.
First possibility:
[tex]x-5=x+5\\0=10[/tex]
No solution.
Second possibility:
[tex]x-5=-(x + 5)\\x-5=-x-5\\2x=0\\x=0[/tex]
Find the 12th term of the following geometric sequence.
10, 30, 90, 270,
Answer:
The 12th term is 1771470Step-by-step explanation:
Since the above sequence is a geometric sequence
An nth term of a geometric sequence is given by
[tex]A(n) = a(r)^{n - 1} [/tex]
where a is the first term
r is the common ratio
n is the number of terms
From the question
a = 10
To find the common ratio divide the previous term by the next term
That's
r = 30/10 = 3 or 90/30 = 3 or 270/90 = 3
Since we are finding the 12th term
n = 12
So the 12th term is
[tex]A(12) = 10( {3})^{12 - 1} [/tex]
[tex]A(12) = 10 ({3})^{11} [/tex]
A(12) = 1771470Hope this helps you
13. If 6 times the 6th term of an A.P. is equal to
13 times the 13th term, prove that 19th term
of this A.P. is zero.
please give the answer as fast as you can
please
Answer:
see explanation
Step-by-step explanation:
The n th term of an AP is
[tex]a_{n}[/tex] = a₁ + (n - 1)d
where a₁ is the first term and d the common difference
Given
6(a₁ + 5d) = 13(a₁ + 12d) ← distribute parenthesis on both sides
6a₁ + 30d = 13a₁ + 156d ( subtract 13a₁ from both sides )
- 7a₁ + 30d = 156d ( subtract 30d from both sides )
- 7a₁ = 126d ( divide both sides by - 7 )
a₁ = - 18d
Now
a₁₉ = a₁ + 18d = - 18d + 18d = 0 ← as required
A recipe for 1 batch of muffins used 2/3 of blueberries. Amir made 2 1/2 batches of muffins. How many cups of blueberries did he use? A. 1 4/6 B. 1 5/6 C. 2 2/6 D. 3 1/6. Please show your work.
Answer:
A. 1 4/6 cups of blueberries
Step-by-step explanation:
1 -- 2/3
Proportion, Batches to Blueberries
1*(2 1/2) -- (2/3)( 2 1/2)
Because we are now multiplying the 1 batch to 2 1/2 batches. So to keep the proportion balanced/equal we are using the same operation on the right side of the proportion
2 1/2 -- (2/3)( 5/2 )
2 1/2 -- 5/3
2 1/2 -- 1 2/3
Simplify
On the right side shows the blueberries for 2 1/2 batches. 1 2/3 = 1 4/6
Hope that helps! Tell me if you need more info
The value of y varies inversely as the square of x, and y = 16, when I = 3.
Find the value of x when y = 1.
Answer:
x = 12Step-by-step explanation:
The statement
The value of y varies inversely as the square of x is written as
[tex]y = \frac{k}{ {x}^{2} } [/tex]
where k is the constant of proportionality
To find the value of x when y = 1 first find the formula for the variation
y = 16 x = 3
k = yx²
k = 16(3)²
k = 16 × 9
k = 144
The formula for the variation is
[tex]y = \frac{144}{ {x}^{2} } [/tex]
when y = 1
We have
[tex]1 = \frac{144}{ {x}^{2} } [/tex]
Cross multiply
x² = 144
Find the square root of both sides
We have the final answer as
x = 12Hope this helps you
Create a circle such that its center is point a and b is a point on the circle
Step-by-step explanation:
The center of a circle is the point in the circle which is equidistant to all the edges of thr circle. The point a is the center, while point b is an arbitrary point in the circle. Find attachment for the diagram.
Answer:
i think that this question is wrong
Step-by-step explanation:
Write the first 4 terms of the sequence defined by the given rule f(n)=n2 -1
Answer:
0, 3, 8, 15Step-by-step explanation:
Substitute n = 1, n = 2, n = 3 and n = 4 to the equation f(n) = n² - 1:
f(1) = 1² - 1 = 1 - 1 = 0
f(2) = 2² - 1 = 4 - 1 = 3
f(3) = 3² - 1 = 9 - 1 = 8
f(4) = 4² - 1 = 16 - 1 = 15
The ratio of oranges in a fruit salad to people it will serve is 9/40, or 9:40. If Lisa wants to serve 800 people, how many oranges will Lisa use?
The correct answer is 180 oranges
Explanation:
In mathematics, a ratio expresses two or more numbers that are related. In the case fo the ration 9: 40 this expresses 9 oranges are used to serve fruit salad for 40 people. Now, if you need to determine what is the number of oranges not for 40 people but for 800 people you can use cross multiplication. This process is explained below:
[tex]\frac{9}{40} = \frac{x}{800}[/tex] - 1. Multiply 9 x 800 and 40 x x (cross multiplication)
[tex]7200 = 40x[/tex] - 2. Solve the equation by diving 7200 into 40
[tex]\frac{7200}{40} = x[/tex]
[tex]x = 180[/tex] - 3. 180 represents the number of oranges to serve 800 people, which can be expressed as 180: 800
A 5-ounce container of Greek yogurt contains 140 calories. Find the unit rate of calories per ounce
Answer:
28
Step-by-step explanation:
140 calories over 5 ounce
= 28
The unit rate of calories per ounce will be 28 calories/ ounce
What is proportion ?
A proportion is an equation based on the equality of two ratios.
It is given that 5-ounce container of Greek yogurt contains 140 calories and it is to calculate for one ounce calories contain in Greek yogurt :
[tex]\begin{aligned}5 \text{\:ounce}&\rightarrow 140 \text{\:calories}\\1 \text{\:ounce}&\rightarrow \frac{140}{5}\text{\:calories} \\&\rightarrow 28 \text{\:calories}\end{aligned}[/tex]
Therefore, the unit rate of calories per ounce will be 28 calories/ ounce
Read more about ratio at:
https://brainly.com/question/17869111
#SPJ2
What is the y-intercept of the line described by the equation below? Y=3x - 6
We are given the equation y = 3x - 6
The slope-intercept form of a line is y = mx + b where m is the slope and b is the y-intercept.
The b value in this equation is -6, thus the y-intercept is -6.
Let me know if you need any clarifications, thanks!
81^x^2=27^x solve for x
Step-by-step explanation:
81^x² = 27^x
(3^4)^x² = (3^3)^x
3^(4x²) = 3^(3x)
4x² = 3x
4x² − 3x = 0
x (4x − 3) = 0
x = 0 or ¾
Find the most general antiderivative of the function. (Check your answer by differentiation. Use C for the constant of the antiderivative.) f(x) = x2 − 7x + 5
Answer:
F(x) = [tex]\frac{x^3}{3} - \frac{7x^2}{2} + 5x + c[/tex]
Step-by-step explanation:
The antiderivative of a function (also called the integration of a function) is the reverse of the differentiation of that function. Given a function f(x), its integration, F(x), can be calculated as follows;
F(x) = [tex]\int\limits{f(x)} \, dx[/tex]
From the question, f(x) = x² - 7x + 5
Therefore,
F(x) = [tex]\int\limits {(x^2 - 7x + 5)} \, dx[/tex]
F(x) = [tex]\frac{x^3}{3} - \frac{7x^2}{2} + 5x + c[/tex]
Where c is the constant of the integration (antiderivative).
PS: The constant of integration is used for indefinite integrals and allows to express integration of a function in its most general form.
The summer has ended and it’s time to drain the swimming pool. 20 minutes after pulling the plug, there is still 45 000L of water in the pool. The pool is empty after 70 minutes. Calculate the rate that the water is draining out of the pool. (Hint: remember this line is sloping down to the right) (3 marks) Rate=0-45000/70-20 Rate = (0 - 45000) / 70-20 Rate = -45000 / 50 Rate=-900/minute b) Calculate how much water was in the pool initially (at time 0). (2 marks)
Answer:
there were 63,000L of water initially in the pool
Step-by-step explanation:
do 900L times the first 20 minutes to find out how much water was drained during the first 20 minutes and you get 18,000L drained
then, add 18,000L plus the rest of the 45,000L of water drained from the pool to get 63,000L of water intially in the pool
What the answer fast
Answer:
HI = 13
Step-by-step explanation:
The triangle that is shown is a 45-45-90 triangle, so we know that GH = GJ = 9 and IJ = 13, we are able to solve for HI.
Technically, IJ = HI, since both triangles are congruent. Both IJ and HI will be 13.
One angle of a right triangle measures 31° what is the measure of the other angle
Answer:
59°
Step-by-step explanation:
A triangle adds up to 180°. A right triangle has a 90° angle.
1. Set up the equation
90 + 31 + x = 180
2. Simplify
121 + x = 180
3. Solve for x by subtracting 121 from both sides
x = 59
1000 randomly selected Americans were asked if they believed the minimum wage should be raised. 600 said yes. Construct a 95% confidence interval for the proportion of Americans who believe that the minimum wage should be raised.
a. Write down the formula you intend to use with variable notation).
b. Write down the above formula with numeric values replacing the symbols.
c. Write down the confidence interval in interval notation.
Answer:
a. p`± z₀.₀₂₅[tex]\sqrt{ \frac{p`q`}{n}[/tex]
b.0.6 ± 1.96 [tex]\sqrt \frac{0.6* 0.4}{1000}[/tex]
c. { -1.96 ≤ p`± z₀.₀₂₅[tex]\sqrt{ \frac{p`q`}{n}[/tex] ≥ 1.96} = 0.95
Step-by-step explanation:
Here the total number of trials is n= 1000
The number of successes is p` = 600/1000 = 0.6. The q` is 1 - p`= 1- 0.6 = 0.4
The degree of confidence is 95 % therefore z₀.₀₂₅ = 1.96 ( α/2 = 0.025)
a. The formula used will be
p`± z₀.₀₂₅[tex]\sqrt{ \frac{p`q`}{n}[/tex] ( z with the base alpha by 2 (α/2 = 0.025))
b. Putting the values
0.6 ± 1.96 [tex]\sqrt \frac{0.6* 0.4}{1000}[/tex]
c. Confidence Interval in Interval Notation.
{ -1.96 ≤ p`± z₀.₀₂₅[tex]\sqrt{ \frac{p`q`}{n}[/tex] ≥ 1.96} = 0.95
{ -z( base alpha by 2) ≤ p`± z₀.₀₂₅[tex]\sqrt{ \frac{p`q`}{n}[/tex] ≥ z( base alpha by 2) } = 1- α
A congressman wants to measure the level of support in his district for campaign finance reform and determine if there is a gender gap among voters with respect to this issue. One aid suggests that they find separate confidence intervals for the percent of men and the percent of women who favor reform and then see if the intervals overlap. Another aid suggests that they find a confidence interval for the difference in the proportions of men and women who favor reform. The question is: Is there a gender gap
Answer:
Campaign Finance Reform
Gender Gap among Voters in the District
There is a gender gap among women and men who favor campaign finance reform.
Step-by-step explanation:
In issues such as the above, a gender gap always exist between women and men who think that there is the need to reform the campaign finance. Women ordinarily favor a reduction in the campaign finance. On the other hand, men do not mind so much about the candidate expenditure in campaigns. Reducing the huge campaign finance will ensure that political campaigns and aspiration to political offices are not left to money bags. Many women would like to get involved, but they are limited by funding. So, anytime the issue of reforming the whole electoral system, especially with respect to campaigns, women favor the reforms more than men. The gap is always there. The main issue is how would this gap be measured?
174 people ate lunch at Alice’s restaurant yesterday, and 1/3 of them had dessert. How many people had dessert after lunch?Explain how you got your answer. (90 points!!!)
Answer:
58 people
Step-by-step explanation:
174 people ate lunch.
1/3 of the 74 people had dessert after lunch.
Multiplying 1/3 and 174.
1/3 × 74
= 58
58 people had desert after lunch.
Answer:
[tex]\boxed{ 58\ people}[/tex]
Step-by-step explanation:
People who ate lunch = 174 people
People among among them who had desserts = 1/3 of the total
(Remember "of" means to "multiply")
=> 1/3 * 174
=> 1 * 58
=> 58 people
-2x(x+3)-(x+1)(x-2)=
Answer:
-3x^2 -5x +2
Step-by-step explanation:
-2x(x+3)-(x+1)(x-2)=
Distribute
-2x^2 -6x -(x+1)(x-2)
Foil
-2x^2 -6x -(x^2 -2x +x -2)
Combine like terms
-2x^2 -6x -(x^2 -x -2)
Distribute the minus sign
-2x^2 -6x -x^2 +x +2
Combine like terms
-2x^2 -x^2 -6x +x +2
-3x^2 -5x +2
Answer:
[tex]\huge\boxed{-2x(x+3)-(x+1)(x-2)=-3x^2-5x+2}[/tex]
Step-by-step explanation:
[tex]-2x(x+3)-(x+1)(x-2)[/tex]
Use the distributive property: a(b + c) = ab + ac
and FOIL: (a + b)(c + d) = ac + ad + bc + bd
[tex]=(-2x)(x)+(-2x)(3)-\bigg[(x)(x)+(x)(-2)+(1)(x)+(1)(-2)\bigg]\\\\=-2x^2-6x-\bigg(x^2-2x+x-2\bigg)=-2x^2-6x-x^2-(-2x)-x-(-2)\\\\=-2x^2-6x-x^2+2x-x+2[/tex]
Combine like terms:
[tex]=(-2x^2-x^2)+(-6x+2x-x)+2=-3x^2+(-5x)+2\\\\=-3x^2-5x+2[/tex]
A theater is presenting a program on drinking and driving for students and their parents or other responsible adults. The proceeds will be donated to a local alcohol information center. Admission is $6.00 for adults and $3.00 for students. However, this situation has two constraints: The theater can hold no more than 240 people and for every two adults, there must be at least one student. How many adults and students should attend to raise the maximum amount of money?
Answer:
160 adults and 80 students
Step-by-step explanation:
With the information from the exercise we have the following system of equations:
Let x = number of students; y = number of adults
I want to maximize the following:
z = 3 * x + 6 * y
But with the following constraints
x + y = 240
y / 2 <= x
As the value is higher for adults, it is best to sell as much as possible for adults.
So let's solve the system of equations like this:
y / 2 + y = 240
3/2 * y = 240
y = 240 * 2/3
y = 160
Which means that the maximum profit is obtained when there are 160 adults and 80 students, so it is true that added to 240 and or every two adults, there must be at least one student.
Question 5 of 13, Step 1 of 1
3/15
Correct
2
The Chandlers are moving across the country. Mr. Chandler leaves 2.5 hours before Mrs. Chandler. If he averages 75 mph and she averages 85 mph, how many hours
will it take Mrs. Chandler to catch up to Mr. Chandler?
Answer:
It will take Mrs Chandler 18 hours 45 minutes or 18.75 hours to catch up Mr Chandler
Step-by-step explanation:
What we want to know here is that at how many hours will they have traveled same distance.
Let the total time taken by Mrs Chandler to catch up be x hours
Since Mr Chandler left 2.5 hours earlier , then the total time taken by him would be x + 2.5 hours
Now, we know that distance = speed * time
Since it’s same distance covered;
For Mr Chandler, his distance is calculated as 75(x + 2.5)
For Mrs Chandler, her distance is calculated as 85x
We equate both since they are equal;
75(x + 2.5) = 85x
75x + 187.5 = 85x
85x -75x = 187.5
10x = 187.5
x = 18.75 hours or 18 hours 45 minutes
What is the following simplified product? Assume x>0
2 square root 8x^3(3 square root 10x^4-x square root 5x^2
Answer:
[tex] 24x^3\sqrt{5x} - 4x^3\sqrt{10x} [/tex]
Step-by-step explanation:
The product [tex]2\sqrt{8x^3} (3\sqrt{10x^4} - x\sqrt{5x^2})[/tex] can be simplified as follows:
Step 1: Use the distributive property of multiplication
[tex]2\sqrt{8x^3}(3\sqrt{10x^4)} - 2\sqrt{8x^3}(x\sqrt{5x^2})[/tex]
[tex] 2*3\sqrt{8x^3*10x^4} - 2*x\sqrt{8x^3*5x^2} [/tex]
[tex] 6\sqrt{80x^7} - 2x\sqrt{40x^5} [/tex]
Step 2: simplify further
[tex] 6\sqrt{16*5*x^3*x^3*x} - 2x\sqrt{4*10*x^4*x} [/tex]
[tex] 6*4*x^3\sqrt{5*x} - 2x*2*x^2\sqrt{10*x} [/tex]
[tex] 24x^3\sqrt{5x} - 4x^3\sqrt{10x} [/tex]
Find the x-coordinates of the two points on the curve
y=x-1/x at which the tangent is parallel to the straight line 4y= x + 8. (4 marks)
Answer: x = {-2, 2}
Step-by-step explanation:
Tangent means it is touching. Find the intersection of the two equations.
Solve the linear equation for y, then set the two equations equal to each other.
[tex]4y=x+8\qquad \rightarrow \qquad y=\dfrac{x+8}{4}[/tex]
[tex]\dfrac{x-1}{x}=\dfrac{x+8}{4}\\\\\\\text{Cross multiply and solve for x:}\\4(x-1)=x(x+8)\\4x-4=x^2+8x\\.\qquad 0=x^2+4x+4\\.\qquad 0=(x+2)^2\\.\qquad 0=x+2\\.\qquad x=-2[/tex]
To find the next point that is parallel to the linear equation and tangent to the curve, we need to use the linear equation with slope (m) = [tex]\dfrac{1}{4}[/tex] and unknown b.
Let's try b = 0, then the equation of the linear equation is: [tex]y=\dfrac{1}{4}x[/tex]
Set the equations equal to each other and solve for x:
[tex]\dfrac{x-1}{x}=\dfrac{x}{4}\\\\\\4(x-1)=x^2\\4x-4=x^2\\.\qquad 0=x^2-4x+4\\.\qquad 0=(x-2)^2\\.\qquad 0=x-2\\.\qquad x=2[/tex]
This works!!! If it didn't work, we would have tried other values for b until we arrived at a solution.
A student is using the elimination method to solve the system of equations below. What is the best first
step?
4x - 5y = 2
2x + y = -3
Answer:
The best first step would be to multiply the second equation by -2
Step-by-step explanation:
The best first step would be to multiply the second equation by -2
then you would have the following
[tex]\ \ \ \ \ \ 4x - 5y = 2 \\-2*(2x)+ (-2)*y = (-2)*3[/tex]
and when you multiply it is easy to eliminate because you will get
[tex]4x - 5y = 2 \\-4x -2y = 6[/tex]
and if you sum the equations you get
-7y = 8
so that is a single variable equation which is easier to solve.
This is a cross-sectional view of candy bar ABC. A candy company wants to create a cylindrical container for candy bar ABC so that it is circumscribed about the candy bar. If = 4 cm, what is the smallest diameter of wrapper that will fit the candy bar?
Answer:
Step-by-step explanation:
No figure supplied, so lots of assumptions needed.
Assume side length of triangle is 4 cm.
( If = 4 cm means ??)
Assume ABC is equiangular, all three angles are 60 degrees.
(This is a cross-sectional view, but don't see any)
Side length = 4
altitude of triangle = 4 sin(60) = 2sqrt(3)
radius of circumscribed circle of equilateral triangle
R = (2/3) altitude
= (2/3)*2sqrt(3)
= (4/3)sqrt(3)
Diameter
D = 2R
= (8/3) sqrt(3)
Answer: 8 cm
Step-by-step explanation:
The figure in the image attached below shows that there are two specific angles that are congruent to each other, angles AD and CD.
We are given the length of one of these angles:
AD= 4 cm so we must multiply 4 by 2, since there are TWO angles measuring 4 cm.
4 cm x 2 angles (AD and CD) =8 cm.
Proof of answer is shown below!
PLZ HELP ITS 20 POINTS Using the linear combination method, what is the solution to the system of linear equations 5 x + 3 y = negative 10 and Negative 20 x minus 7 y = 15? (–5, 1) (–1, 5) (1, –5) (5, –1)
Answer:
The answer is (1,-5). (i.e x=1 and y=-5).
Hope it helps..
Answer:
(1,-5)
Step-by-step explanation: