How much was Kenny's allowance?

Question

Kenny spent $80 of his allowance on food, 2/5 of the remainder on stationery and saved the rest. He saved 1/3 of his allowance. How much was Kenny's allowance?

Answer 1

Let A = allowance

He spent 80 + (2/5)(A - 80)

He has left A - [80 + (2/5)(A - 80)]

and he has left A/3

Therefore

A - [80 + (2/5)(A - 80)] = A/3 or (2/3)A = 80 + (2/5)(A - 80)

Clear fractions (multiply by 15)

10A = 1200 + 6(A - 80)

10A = 1200 + 6A - 480

4A = 720

A = 180

NICE ALLOWANCE!!!!!