Question

A girl scout troop sold cookies. If the girls sold 5 more boxes the second week than they did the first, and if they doubled the sales of the second week for the third week to sell a total of 431 boxes of cookies, how many did they sell each week?

Answer 1

week1 = x

week2 = x+5

week3 = 2(x+5)

x + (x+5) + 2(x+5) = 431

x + x + 5 + 2x + 10 = 431

4x + 15 = 431

4x = 431 - 15

4x = 416

x = 104

week1 = x = 104 boxes

week2 = x+5 = 104+5 = 109 boxes

week3 = 2(x+5) = 2(104+5) = 2*109 = 218 boxes