Question

Suppose you have $55 in your bank account. You start saving $10 each week. Your friend has $20 in her account and is saving $15 each week. When will you and your friend have the same amount of money in your accounts?
A. 6 weeks
B. 8 weeks
C. 7 weeks
D. 5 weeks

Answer 1

$ you have will be represented by y
$ your friend has will be f
The amount of weeks you save up for will be w
y=55+10w
f=20+15w
now set them equal to each other
55+10w=20+15w
Move all variables to one side and all constants to the other
55-20=15w-10w
combine like terms
35=5w
isolate the variable
35/5=w
combine like terms
7=w
it will take 7 weeks

Answer 2

Answer:

7 weeks

Explanation:

Let w = the number of weeks.

Let A(w) = the amount of money saved after w weeks.

The amount saved A(w) is the starting amount plus weekly savings.

A(w) = 55 + 10w

A(w) = 20 + 15w

Graph the equations on the same coordinate plane.

The lines intersect at (7, 125). After 7 weeks, you and your friend will have the same amount, $125, in your accounts.