Question

x + y = 28

y = 2x - 5



y = Marci; x = Jennifer



Jennifer and Marci are selling cookies for a fundraiser. They sold 28 boxes of cookies together. Marci sold 5 less than twice the number that Jennifer sold. How many boxes of cookies did each girl sell? Use system of equations to solve the problem.

Answer 1

Let x = Jennifer, y = Marci.

System:
x + y = 28
y = 2x − 5

Substitute y into the first equation:
x + (2x − 5) = 28
3x − 5 = 28
3x = 33
x = 11

Then y = 2(11) − 5 = 22 − 5 = 17.

So Jennifer sold 11 boxes and Marci sold 17 boxes.