Question

After spending 1/4 of his allowance on a book and 1/3 of the remainder on stationery, John has $18 left. Find the cost of the book.

Answer 1

This problem is tricky. Let's break it down.

1/4 - book

------------------------------------------------------

1/3 of the remainder(3/4) - stationery

"OF" MEANS MULTIPLY

1/3 x 3/4 = 1/4

So, 1/4 of total allowance on stationery.

Meaning, he spent 1/2 of his allowance in all, and 1/2 of his allowance is $18.

Since the book cost 1/4 of his allowance, and (1/4)2 = 1/2, the book cost 18/2 = $9.