Answer:
<u>Part A: </u>
<u>n = 5q (1st equation)</u>
<u>0.05n + 0.25q = 2 (2nd equation)</u>
<u>Part B:</u>
<u>q = 4 ⇒ n = 5 * 4 = 20</u>
<u>Part C:</u>
<u>Margie has 20 nickels and 4 quarters, for a total of $ 2.00</u>
Step-by-step explanation:
Let's recall that a nickel has a value of $ 0.05 and a quarter a value of $ 0.25.
Let n represent the number of nickels and q represent the number of quarters.
Part A:
Write a system of equations to represent the situation.
n = 5q (1st equation)
n * 0.05 + q * 0.25 = 2
0.05n + 0.25q = 2 (2nd equation)
Part B:
Replacing n in the 2nd equation to solve for q:
0.05n + 0.25q = 2
0.05 * 5q + 0.25q = 2
0.25q + 0.25q = 2
0.5q = 2
q = 2/0.5
<u>q = 4 ⇒ n = 5 * 4 = 20</u>
<u>Part C:</u>
<u>Margie has 20 nickels and 4 quarters, for a total of $ 2.00</u>
The points where the 2 graphs intersect is where x = 0 and x = 2.
- 2 2
x = INT x dA / INT dA
0 0
INT dA = INT -x^2 + 4x + 3 - (x^2 + 3 ) dx = INT -2x^2 + 4x
= -2 x^3/3 + 2x^2
= 2.667 between 0 and 2
xdA = -2x^3 + 4x^2 INT xdA = -x^4/2 + 4x^3/3 = 2.667
centroid = 2.667 / 2.667 = 1 (x = 1)
The answer would be the first choice. 
Explanation: The reason for this is that the question was pretty much just asking what the area of the resulting two-dimensional cross section would be -the shape in gray- (which can be found by using the formula 
. To add on, since the dimensions of the shape are already given (5 and 3) all you've to do is multiply: 3*5=15
That's how you get to the answer.
I believe the answer is C!
