Question

Solve this problem:
A girl scout troop sold cookies. The girls sold 5 more boxes the second week than they did the first. They doubled the sales of the second week for the third week to sell a total of 431 boxes of cookies. How many boxes of cookies did they sell each week?

Answer 1

let

x = amount sold in first week
y = amount sold in second week
z = amount sold in third week

Answer 2

The girls sold 5 more boxes the second week than they did the first

means

y = x+5

Answer 3

They doubled the sales of the second week for the third week

means

z = 2y

Answer 4

they sold a total of 431 boxes, which means

x+y+z = 431

Answer 5

Now solve y = x+5 for x to get

x = y - 5

Answer 6

then plug in x = y-5 and z = 2y into x+y+z = 431

x+y+z = 431

y-5+y+2y = 431

Solve that for y. Then use that solution of y to find solutions for x and z

Answer 7

So, they sold 104 boxed the first week. 109 the second and 218 the third.

Answer 8

I'm getting the same and I just checked the answer and it all works out

nice job

Answer 9

Thanks.

Answer 10

yw