Abi had some money. She spent 30% on food and 25% of her remaining money on a blazer. She had $315 left.

1. How much did she have at first?
2. If the blazer was bought at a 30% discount, what was the original price of the blazer?

(a)
Percent of Abi's amount left after she spent on food
= 100% - 30%
= 70%

Percent of Abi's remaining amount left after she spent on the blazer
= 100% - 25%
= 75%

Fraction of Abi's amount left
= 75% x 70% 
= ⁷⁵₁₀₀ x ⁷⁰₁₀₀
= ²¹₄₀

Total amount that Abi had = 40 u
Amount that Abi had left = 21 u

21 u = 315

1 u = 315 ÷ 21 = 15

Amount that Abi had at first
= 40 u
= 40 x 15
= $600

(b)
Fraction of Abi's amount spent on the blazer
= 25% x 70% 
= ²⁵₁₀₀ x ⁷⁰₁₀₀ 
= ⁷₄₀

Amount that Abi spent on the blazer
= 7 u
= 7 x 15
= $105

Discounted price of the blazer in percent
= 100% - 30%
= 70%

70% of the price of the blazer = 105
1% of the price of the blazer = 105 ÷ 70 = 1.5
100% of the price of the blazer = 100 x 1.5 = 150

Original price of the blazer = $150

Answer(s): (a) $600; (b) $150