Currently, you have $80 and your sister has $145. You decide to save $6 of your allowance each week, while your sister decides to spend her whole allowance plus $7 each week. How long will it be before you have as much money as your sister?

Answer 1

80 + 6x = 145 - 7x
13x = 65
x = 5
After 5 weeks both of you will have $110