Abi spent 60% of her money on a number of erasers. She spent 30% of the remaining money on a few stamps and 50% of what was left on a number of stickers.

1. What fraction of her money was left?
2. Given that the erasers cost $69 more than the stickers, find the sum of money Abi had at first.

(a)
60% = ⁶⁰₁₀₀ = ³₅

Fraction of money left after buying the erasers = 1 - ³₅ = ²₅

30% = ³⁰₁₀₀ = ³₁₀

Fraction of remaining money after buying the stamps = 1 - ³₁₀ = ⁷₁₀ 

50% = ⁵⁰₁₀₀ = ¹₂

Fraction of what is left after buying the stickers = 1 - ¹₂ = ¹₂

Fraction of money left after buying the erasers
= ²₅ x ⁷₁₀ x ¹₂
= ⁷₅₀

(b)
Fraction of money spent on the stickers
= ²₅ x ⁷₁₀ x ¹₂
= ⁷₅₀

Fraction of money spent on the erasers
= ³₅
= ³⁰₅₀

Amount spent more on the erasers than the stickers
= 30 u - 7 u
= 23 u

23 u = 69

1 u = 69 ÷ 23 = 3

Amount that Abi had at first
= 50 u
= 50 x 3
= $150

Answer(s): (a) ⁷₅₀; (b) $150