Question

Gomez gives his cousin 1/3 of his stamps. He then gives his sister 5/6 of the remaining and has 80 stamps left. How many stamps did he start out with?

Answer 1

He gave away x/3 leaving him with 2x/3

He then gave away 5/6 of the remainder or (5/6)(2x/3) = 5x/9

So he has 2x/3 - 5x/9 left and this totals to 80

2x/3 - 5x/9 = 80

Multiply through by 9 to clear fractions

6x - 5x = 720

x = 720