Question

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

Answer 1

You can solve the problem this way:

Your money is increading $6 a week while sister's is decreasing $7 a week (because she isn't saving any and is spending $7 of what she has weekly)

Your money each additional week vs sister''s:

80/145 (Week 0)

86/138 (Week 1)

92/131 (Week 2)

98/124 (Week 3)

104/117 (Week 4)

110/110 (Week 5) The amounts are the same in 5 weeks.