Answer:
3$per chair
Step-by-step explanation:
50/150$=3
If 3 x 50=150
Answer:
150/50
Step-by-step explanation:
150 divided by 50 = 3
Hope this helps!
A human resources office is working to implement an increase in starting salaries for new
administrative secretaries and faculty at a community college. An administrative secretary
starts at $28,000 and new faculty receive $40,000. The college would like to determine the
percentage increase to allocate to each group, given that the college will be hiring 8
secretaries and 7 faculty in the upcoming academic year. The college has at most $5,000 to
put towards raises. What should the percentage increase be for each group?
Answer:
Step-by-step explanation :
Let % increase in administrative secretary be = x
Let % increase in new faculty receive be = y
Administrative secretary salary = 28,000
New faculty receive Salary = 40,000
(8)*(x/100)* (28000) + (7)*(y/100)*(40000) = 5,000
2240x +2800 y = 5,000
224x +280 y = 500
56x +70y = 125
Therefore, x and y should be chosen such that it satisfy the above equation.
Solve the following equation by first writing the equation in the form a x squared = c:
3 a squared minus 21 = 27
A. a = 4
B. a = plus-or-minus 4
C. a = plus-or-minus 16
D. a = 16
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Answer:
B. a = plus-or-minus 4
Step-by-step explanation:
3a² -21 = 27 . . . . . . . given
3a² = 48 . . . . . . . . . . add 21 to both sides (desired form)
a² = 16 . . . . . . . . . . . divide both sides by 3
a = ±4 . . . . . . . take the square root
Given: Line AC is parallel to DF, Line BE is perpendicular to DF, and angle AEB is congruent to angle CEB, prove angle BAE is congruent to angle BCE. Will give Brainliest if explained thoroughly.
9514 1404 393
Explanation:
There are several ways you can go at this. Here are a couple. All proofs will start with the given relations being repeated as part of the proof. Here are the next steps.
Angle Sum∠AED ≅ ∠BAE . . . . alternate interior angles are congruent
∠AED +∠AEB = 90° . . . . angle sum theorem
∠BAE +∠AEB = 90° . . . . substitution property of equality
∠CEF ≅ ∠BCE . . . . alternate interior angles are congruent
∠CEF +∠CEB = 90° . . . . angle sum theorem
∠BCE +∠CEB = 90° . . . . substitution property of equality
∠BAE +∠AEB = ∠BCE +∠CEB . . . . substitution property of equality
∠BAE +∠AEB = ∠BCE +∠AEB . . . . substitution property of equality
∠BAE = ∠BCE . . . . addition property of equality
Congruent Triangles∠ABE = ∠CBE = 90° . . . . BE ⊥ AC
BE ≅ BE . . . . reflexive property of congruence
ΔBEA ≅ ΔBEC . . . . ASA congruence theorem
∠BAE ≅ ∠BCE . . . . CPCTC
If the total income generated from Gasoline for AER was $408 millions, how much would be the cost for a barrel of gasoline
14. In a statistics class with 15 males and 13 females, five students are selected to put problems on the board. What is the probability that:
a. 3 females and 2 males are selected? b.all five students selected are males? c. all five students selected are females? d.at least one male is selected?
Answer:
a) 0.3056 = 30.56% probability that 3 females and 2 males are selected.
b) 0.0306 = 3.06% probability that all five students selected are males.
c) 0.0131 = 1.31% probability that all five students selected are females.
d) 0.9869 = 98.69% probability that at least one male is selected.
Step-by-step explanation:
The students are chosen from the sample without replacement, which means that the hypergeometric distribution is used to solve this question.
Hypergeometric distribution:
The probability of x successes is given by the following formula:
[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}[/tex]
In which:
x is the number of successes.
N is the size of the population.
n is the size of the sample.
k is the total number of desired outcomes.
In this question:
15 + 13 = 28 students, which means that [tex]N = 28[/tex]
5 are selected, which means that [tex]n = 5[/tex]
13 females, which means that [tex]k = 13[/tex]
a. 3 females and 2 males are selected?
3 females, so this is P(X = 3).
[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}[/tex]
[tex]P(X = 3) = h(3,28,5,13) = \frac{C_{13,3}*C_{15,2}}{C_{28,5}} = 0.3056[/tex]
0.3056 = 30.56% probability that 3 females and 2 males are selected.
b.all five students selected are males?
0 females, so this is P(X = 0).
[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}[/tex]
[tex]P(X = 0) = h(0,28,5,13) = \frac{C_{13,0}*C_{15,5}}{C_{28,5}} = 0.0306[/tex]
0.0306 = 3.06% probability that all five students selected are males.
c. all five students selected are females?
This is P(X = 5). So
[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}[/tex]
[tex]P(X = 5) = h(5,28,5,13) = \frac{C_{13,5}*C_{15,0}}{C_{28,5}} = 0.0131[/tex]
0.0131 = 1.31% probability that all five students selected are females.
d.at least one male is selected?
Less than five females, so:
[tex]P(X < 5) = 1 - P(X = 5) = 1 - 0.0131 = 0.9869[/tex]
0.9869 = 98.69% probability that at least one male is selected.
Test for symmetry and then graph the polar equation.
r=3−5sinθ
Answer:
Symmetric with respect to the x-axis
Symmetric with respect to the y-axis
Symmetric with respect to the origin
Help with solving this Functions problem
Answer:
See answers below
Step-by-step explanation:
Given the following functions:
r(x) = x - 6
s(x) = 2x²
r(s(x)) = r(2x²)
Replacing x with 2x² in r(x) will give;
r(2x²) = 2x² - 6
r(s(x)) = 2x² - 6
(r-s)(x) = r(x) - s(x)
(r-s)(x) = x - 6 - 2x²
Rearrange
(r-s)(x) = - 2x²+x-6
(r+s)(x) = r(x) + s(x)
(r-s)(x) = x - 6 + 2x²
Rearrange
(r-s)(x) = 2x²+x-6
which of the folleing is a statistical question?
a) how tall is steve?
b)what are the heights of students in class?
c)what is the formula for the volume of the cube?
d) what is the address of the white house?
I need help I don’t understand at all ?
Answer:
i think its the 3 line. they are congruent.
Answer:
its the 3rd option
Step-by-step explanation:
first of all AA means angle-angle which means we are using their angles to compare them
second, those lines on the sides are only there to tell you they are in the exact same angle, and the two boxes on the bottom show that the angle of both triangles is 90° therefore they are the same
In a poll, adults in a region were asked about their online vs. in-store clothes shopping. One finding was that % of respondents never clothes-shop online. Find and interpret a % confidence interval for the proportion of all adults in the region who never clothes-shop online.
The question is incomplete. The complete question is :
In a poll, 1100 adults in a region were asked about their online vs. in-store clothes shopping. One finding was that 43% of respondents never clothes-shop online. Find and interpret a 95% confidence interval for the proportion of all adults in the region who never clothes-shop online.
Solution :
95% confidence interval for p is :
[tex]$\hat p - Z_{\alpha/2}\times \sqrt{\frac{\hat p(1-\hat p)}{n}} < p < \hat p + Z_{\alpha/2}\times \sqrt{\frac{\hat p(1-\hat p)}{n}}$[/tex]
[tex]$0.43 - 1.96\times \sqrt{\frac{0.43(1-0.43)}{1100}} < p < 0.43 + 1.96\times \sqrt{\frac{0.43(1-0.43)}{1100}}$[/tex]
0.401 < p < 0.459
Therefore, 95% confidence interval is from 0.401 to 0.459
Which sequence or sequences are correct and why?
Answer:
didn't get the question did u forget to put the sequence ???????
pls write the question fully so that I can help you
F(4) =
If g(x) = 2, x=
An
Step-by-step explon:
A paper factory makes cardboard sheets like the one shown below. If the area of each sheet is given by the expression 6x ^ 2 + 7x + 2, what are the dimensions of each sheet of cardboard?
Answer:
(3x+2) by (2x+1)
Step-by-step explanation:
A cardboard is a rectangle, and has two dimensions. Given a quadratic equation, you should find a way to split it in two.
The easiest way to do so is through factoring. (There are many ways to do this, take a look at the plethora of sources offered on the internet.)
When the expression 6x^2 + 7x + 2 is factored, it is (3x+2)(2x+1). Hence, these are your dimensions.
Can someone help me solve this Please
9514 1404 393
Answer:
523 grams52 gramsStep-by-step explanation:
To find the initial amount, put 0 where t is in the formula and do the arithmetic.
A(0) = 523(1/2)^0 = 523(1) = 523
The initial amount is 523 grams.
__
To find the amount remaining after 100 years, put 100 where t is in the formula and do the arithmetic.
A(100) = 523(1/2)^(100/30) ≈ 523(0.0992123) ≈ 52
About 52 grams will remain after 100 years.
The square pyramid shown below has a base with sides of 10 units. The slant height of the pyramid is 8 units. What is the vertical height, h?
Round your answer to the nearest tenth.
Answer:
h = 6.2 units
Step-by-step explanation:
Given triangle ABC is a right triangle with the measures of the two sides,
BC = [tex]\frac{10}{2}[/tex] = 5 units
AC = 8 units
By applying Pythagoras theorem in the given triangle,
AC² = AB² + BC²
8² = AB² + 5²
AB² = 64 - 25
AB = √39
AB = 6.24 units
AB ≈ 6.2 units
PLEASE HELPPP THIS IS DUE ASAPPPP!!!!!!!!!!!!!! WILL GIVE BRAINLIEST
Answer:
I think the answer is 5/6
Step-by-step explanation:
There are three even numbers and two uneven numbers less than four. Therefore, on a standard die, the.probability of Rollin a number that is even or less than for is 5/6.
For any event, P(A) + P(not A) =
Explanation:
P(A) represents the probability of event A
P(not A) is the probability that event A doesn't happen
We only have two choices: Either A happens or it doesn't
So that means P(A) + P(not A) = 1
The "1" represents a 100% chance, aka certainty.
help with b please. thank you
Answer:
See explanation.
General Formulas and Concepts:
Algebra I
Terms/CoefficientsFactoringAlgebra II
Polynomial Long DivisionPre-Calculus
ParametricsCalculus
Differentiation
DerivativesDerivative NotationDerivative Property [Multiplied Constant]: [tex]\displaystyle \frac{d}{dx} [cf(x)] = c \cdot f'(x)[/tex]
Derivative Property [Addition/Subtraction]: [tex]\displaystyle \frac{d}{dx}[f(x) + g(x)] = \frac{d}{dx}[f(x)] + \frac{d}{dx}[g(x)][/tex]
Basic Power Rule:
f(x) = cxⁿf’(x) = c·nxⁿ⁻¹Derivative Rule [Quotient Rule]: [tex]\displaystyle \frac{d}{dx} [\frac{f(x)}{g(x)} ]=\frac{g(x)f'(x)-g'(x)f(x)}{g^2(x)}[/tex]
Parametric Differentiation: [tex]\displaystyle \frac{dy}{dx} = \frac{\frac{dy}{dt}}{\frac{dx}{dt}}[/tex]
Step-by-step explanation:
Step 1: Define
Identify
[tex]\displaystyle x = 2t - \frac{1}{t}[/tex]
[tex]\displaystyle y = t + \frac{4}{t}[/tex]
Step 2: Find Derivative
[x] Differentiate [Basic Power Rule and Quotient Rule]: [tex]\displaystyle \frac{dx}{dt} = 2 + \frac{1}{t^2}[/tex][y] Differentiate [Basic Power Rule and Quotient Rule]: [tex]\displaystyle \frac{dy}{dt} = 1 - \frac{4}{t^2}[/tex]Substitute in variables [Parametric Derivative]: [tex]\displaystyle \frac{dy}{dx} = \frac{1 - \frac{4}{t^2}}{2 + \frac{1}{t^2}}[/tex][Parametric Derivative] Simplify: [tex]\displaystyle \frac{dy}{dx} = \frac{t^2 - 4}{2t^2 + 1}[/tex][Parametric Derivative] Polynomial Long Division: [tex]\displaystyle \frac{dy}{dx} = \frac{1}{2} - \frac{7}{2(2t^2 - 1)}[/tex] [Parametric Derivative] Factor: [tex]\displaystyle \frac{dy}{dx} = \frac{1}{2} \bigg( 1 - \frac{9}{2t^2 + 1} \bigg)[/tex]Here we see that if we increase our values for t, our derivative would get closer and closer to 0.5 but never actually reaching it. Another way to approach it is to take the limit of the derivative as t approaches to infinity. Hence [tex]\displaystyle \frac{dy}{dx} < \frac{1}{2}[/tex].
Topic: AP Calculus BC (Calculus I + II)
Unit: Parametrics
Book: College Calculus 10e
What is the difference of the two polynomials? (NineX squared plus 8X) minus (twoX squared plus 3X)
Answer:
[tex]7x {}^{2} + 5x[/tex]
Step-by-step explanation:
[tex]9x {}^{2} + 8x - (2x {}^{2} + 3x) \\ \\ = 9x {}^{2} + 8x - 2x {}^{2} - 3x (remove \: brackets) \\\ \\ = 7x {}^{2} - 5x [/tex]
Please please help me i can’t figure this out .. ernest's friend rolls a six-sided number cube and lands on square 8. She asks Ernest to guess what number she rolled. He guesses that she rolled a 3. She says he's wrong.
ernest wonders if she could have rolled a number other than 3. Use a mapping diagram to help guess what number she rolled.
If she would have rolled
Create a Mapping Diagram
When playing this game, the square you land on during the first turn depends on the number you roll. You can write this as a function: SQUARE(number), or S(n). For example, if you roll a 2, you end up on square 2 (when you land on 3 you move back a space). So S(2) = 2.
1. Describe the possible inputs of S(n) using words. (2 points: 1 point for the description, 1 point for the list of numbers)
2. Describe the possible outputs of S(n) using words. (1 point)
3. Draw a mapping diagram for S(n) that maps all the possible inputs and outputs for a player's first turn. Note that the player should begin on square 1. (6 points: 3 points for the inputs and outputs, and 3 points for the mapping)
4. In the mapping diagram you created, what numbers are in the domain of S(n)? Explain what this means. (2 points: 1 point for the domain, 1 point for the explanation)
5. What numbers are in the range of S(n)? Explain what this means. (2 points: 1 point for the range, 1 point for the explanation)
Evaluate the Conjecture
6. Based on the mapping diagram, is it possible that the player rolled a number other than 3 to land on square 8? If so, which number or numbers? Explain your answer. (2 points: 1 point for the answer, and 1 point for the explanation)
Defining Functions
7. Does the mapping diagram you created for S(n) for the first turn of the game represent a function? Why or why not? (2 points: 1 point for the answer, and 1 point for the explanation)
Step-by-step explanation:
1. The inputs are the dice values. Since the cube is six sided, the possible. values are (1,2,3,4,5,6).
2. The outputs values are points if we roll the number. If we land in a special space, we must respect that rule so our outputs are
(2,2,8,5,6,8).
3. I cant show a mapping diagram on brainly. Draw a mapping diagram and make sure to connect the x values and y values of the following.Also make sure to start on square 1.
1 corresponds with 22 corresponds with 23 corresponds with 84 corresponds with 55 corresponds with 66 corresponds with 84. The domain of the function is the same as the input. The dice values, 1,2,3,4,5,6
5.The range are the. values that occur if we roll the number about square 1.
2,2,8,5,6,8
6. No, the player could have rolled 3 and landed on 8. The player also could have rolled 6.
7. Yes, every one x value corresponds with one y value.
A machine in a factory must be repaired if it produces more than 10% defectives in production. A random sample of 100 items from a day's production contains 15 defectives, and the foreman says that the machine must be repaired. Statistically, does the sample evidence support his decision to repair at the 0.01 significance level? Conduct a test by using both the critical region method and the p-value method.
From the test the person wants, and the sample data, we build the test hypothesis, find the test statistic, and use this to reach a conclusion both using the critical value and the p-value.
Doing this, the conclusions are:
The test statistic is [tex]z = 1.67 < z_c[/tex], meaning that there is not enough evidence to conclude that the proportion of defectives is above 10%, that is, it does not support his decision to repair at the 0.01 significance level.The p-value of the test is 0.0475 > 0.01, meaning that there is not enough evidence to conclude that the proportion of defectives is above 10%, that is, it does not support his decision to repair at the 0.01 significance level.---------------------------------------------------------
Hypothesis:
A machine in a factory must be repaired if it produces more than 10% defectives in production.
At the null hypothesis, we test if it does not have to be repaired, that is, the proportion is of at most 10%. So
[tex]H_0: p \leq 0.1[/tex]
At the alternative hypothesis, we test if it does have to be repaired, that is, the proportion is greater than 10%. So
[tex]H_1: p > 0.1[/tex]
------------------------------------------------------
Decision rule:
0.01 significance level, using a left-tailed test(testing if the mean is more than a value), which means that:
The critical value is Z with a p-value of 1 - 0.01 = 0.99, so [tex]Z_c = 2.327[/tex]. If the test statistic z is less than this, there is not enough evidence to reject the null hypothesis, that the proportion is of at most 10%, otherwise, there is.The p-value is the probability of finding a sample proportion above the one found. If it is more than 0.01, there is not enough evidence to reject the null hypothesis, otherwise, there is.----------------------------------------------------------
The test statistic is:
[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
In which X is the sample mean, is the value tested at the null hypothesis, is the standard deviation and n is the size of the sample.
0.1 is tested at the null hypothesis:
This means that [tex]\mu = 0.1, \sigma = \sqrt{0.1*0.9}[/tex]
A random sample of 100 items from a day's production contains 15 defectives.
This means that [tex]n = 100, X = \frac{15}{100} = 0.15[/tex]
Value of the test-statistic:
[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
[tex]z = \frac{0.15 - 0.1}{\frac{\sqrt{0.1*0.9}}{\sqrt{100}}}[/tex]
[tex]z = 1.67[/tex]
----------------------------------------------
Decision: Critical region
The test statistic is [tex]z = 1.67 < z_c[/tex], meaning that there is not enough evidence to conclude that the proportion of defectives is above 10%, that is, it does not support his decision to repair at the 0.01 significance level.
Decision: p-value
The p-value of the test is the probability of finding a sample proportion above 0.15, which is 1 subtracted by the p-value of z = 1.67.
Looking at the z-table, z = 1.67 has a p-value of 0.9525.
1 - 0.9525 = 0.0475.
The p-value of the test is 0.0475 > 0.01, meaning that there is not enough evidence to conclude that the proportion of defectives is above 10%, that is, it does not support his decision to repair at the 0.01 significance level.
A similar problem is found at https://brainly.com/question/24326664
5(6t-3)=5t+35
find the value of t
Answer:
t = 2
Step-by-step explanation:
5(6t-3)=5t+35
Step 1 distribute the 5 by multiplying 5 to what is inside of the parenthesis
5(6t) - 5(3) = 5t + 35
Outcome: 30t - 15 = 5t + 35
Step 2 add 15 to both sides
30t - 15 + 15 = 5t + 35 + 15
Outcome: 30t = 5t + 50
Step 3 subtract 5t from both sides
30t - 5t = 5t - 5t + 50
Outcome: 25t = 50
Step 4 divide both sides by 25
25t/25 = 50 we're left with t = 2
HELP PLEASE ASAP!!! So for this problem I got the scientific notation however I can not seem to figure out the standard notation. Can someone please help me out here please?
Answer:
0.000000073
Step-by-step explanation:
Given number is,
7.3E - 8
In scientific notation number will be,
7.3 × 10⁻⁸
In standard form the number will be,
0.000000073
Use the figure to find u.
Answer:
u = 2
Step-by-step explanation:
Since this is a right triangle, we can use trig functions
cos theta = adj side / hypotenuse
cos 45 = sqrt(2) / u
u cos 45 = sqrt(2)
u = sqrt(2) / cos 45
u = sqrt(2) / 1/ sqrt(2)
u = sqrt(2) * sqrt(2)
u =2
u=2
Answer:
Solution given:
Relationship between base and hypotenuse is given by cos angle.Cos 45°=base/hypotenuse
[tex]\frac{1}{\sqrt{2}}=\frac{\sqrt{2}}{u}[/tex]
doing crisscrossed multiplication
[tex]\sqrt{2}*\sqrt{2}=1*u[/tex]
u=2
Suppose the amount of protein is at least 8.6 grams. What is the probability that it is more than 8.7 grams
This question is incomplete, the complete question is;
Many people grab a granola bar for breakfast or for a snack to make it through the afternoon slump at work. A Kashi GoLean Crisp Chocolate Caramel bar weighs 45 grams. The mean amount of protein in each bar is 8 grams. Suppose the amount of protein in the bars have a normal distribution with a standard deviation of 0.32 grams and a random Kashi bar is selected.
Suppose the amount of protein is at least 8.6 grams. What is the probability that it is more than 8.7 grams
Answer:
the required probability is 0.472
Step-by-step explanation:
Given the data in the question;
Let x represent the random variable that shows the protein in the bar.
{ normal distribution }
mean μ = 8
standard deviation σ = 0.32
Now, Suppose the amount of protein is at least 8.6 grams. What is the probability that it is more than 8.7 grams
first we get the z-score for x = 8.6
z = x - μ / σ
z = ( 8.6 - 8 ) / 0.32
z = 0.6 / 0.32
z = 1.875
so
P( x ≥ 8.6 ) = P( z ≥ 1.875 ) = 1 - 0.9696 = 0.0304
Also for, x = 8.7
z = x - μ / σ
z = ( 8.7 - 8 ) / 0.32
z = 0.7 / 0.32
z = 2.1875
so
P( x > 8.7 ∩ x ≥ 8.6 ) = P( x > 8.7 ) = P( z > 2.1875 ) = 1 - 0.98565 = 0.01435
Now, the required probability will be;
P( x > 8.7 | x ≥ 8.6 ) = [P( x > 8.7 ∩ x ≥ 8.6 )] / [ P( x ≥ 8.6 ) ]
= 0.01435 / 0.0304
= 0.472
Therefore, the required probability is 0.472
Jeff has 20 coins. 2/5 of them are quarters. How many quarters does he have? How many coins are not quarters?
if ax^3+9x^2+4x-10 when divided by x-3 leaves the reminder 5,then a=
Let f(x) = ax³ + 9x² + 4x – 10
g(x) = 0⇒x - 3 = 0
⇒ x = 0 + 3
⇒ x = 3
On dividing f(x) by x - 3, it leaves a remainder 5.
Now keeping, f(3) = 5
⇒a(3)³ + 9(3)² + 4(3) - 10 = 5
⇒ a × 27 + 9 × 9 + 4 × 3 - 10 = 5
⇒ 27a + 81 + 12 - 10 = 5
⇒ 81 + 12 - 10 - 5 = 27a
⇒ 81 + 12 - 15 = 27a
⇒ 93 - 15 = 27a
⇒ 78 = 27a
⇒ a = 27/78
⇒ a = 0.3461
A class contains 18 girls and 14 boys. For all parts of this question, each boy and girl are distinguishable from one another. Answer the following questions:a)In how many ways can a committee of one boy and one girl be chosen
Answer:
The total number of ways is 252.
Step-by-step explanation:
Number of girls = 18
number of boys = 14
Commitee of one girl and a boy
(18 C 1)(14 C 1)
= 252
What is 23– 48? Need awnser now
Each side of a square is increasing at a rate of 8 cm/s. At what rate (in cm2/s) is the area of the square increasing when the area of the square is 49 cm2
Answer:
Step-by-step explanation:
This is nice and simple. I'm going to walk through it like I do when teaching this concept to my class for the first time. This is a good problem for that.
We are given a square and we are looking for the rate at which the area is increasing when a certain set of specifics are given. That means that the main equation for this problem is the area of a square, which is:
[tex]A=s^2[/tex] where s is a side.
Since we are looking for the rate at which the area is changing, [tex]\frac{dA}{dt}[/tex], we need to take the derivative of area formula implicitly:
[tex]\frac{dA}{dt}=2s\frac{ds}{dt}[/tex] that means that if [tex]\frac{dA}{dt}[/tex] is our unknown, we need values for everything else. We are given that the initial area for the square is 49. That will help us determine what the "s" in our derivative is. We plug in 49 for A and solve:
[tex]49=s^2[/tex] so
s = 7
We are also given at the start that the sides of this square are increasing at a rate of 8cm/s. That is [tex]\frac{ds}{dt}[/tex]. Filling it all in:
[tex]\frac{dA}{dt}=2(7)(8)[/tex] and
[tex]\frac{dA}{dt}=112\frac{cm^2}{s}[/tex]
The surface area of a square of side L is given by
[tex]A = L^2[/tex]
The rate of change of the area per unit time is
[tex]\dfrac{dA}{dt} = 2L\dfrac{dL}{dt}[/tex]
We can express the length L on the right hand side in terms of the area A [tex](L = \sqrt{A})[/tex]:
[tex]\dfrac{dA}{dt} = 2\sqrt{A}\dfrac{dL}{dt}[/tex]
[tex]\:\:\:\:\:\:\:=2(\sqrt{49\:\text{cm}^2})(8\:\text{cm/s})[/tex]
[tex]\:\:\:\:\:\:\:=112\:\text{cm}^2\text{/s}[/tex]
