how many did they sell each week?

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?

They sold___boxes the first week,___boxes the second week, and___boxes the third week.

Answer 1

w1: x
w2: x+5
w3: 2(x+5)
total= 431

x+x+5+2(x+5)=431
x+x+5+2x+10=431
4x+15=431
4x=416
x=104

w1= 104
x2= 109
w3= 218

Answer 2

Okay, letting x be how many they sold first week, then they sold 5+x 2nd week, and they sold 2(5+x) = 10+2x third week.
Then x+(5+x)+(10+2x)=431.
Or 4x+15=431. So, x=(431-15)/4 = 104.

So,
They sold 104 boxes for first week, 109 boxes the second week, and 218 boxes the third week.