Bryan and Pierre went to buy hi-fi systems at a sale. The usual price of 1 hi-fi system was $500 each.

SALE
Buy 1 hi-fi system at 15% discount
Buy 2 or more hi-fi systems at 20% discount each

1. Bryan bought 1 hi-fi system. How much did he pay?
2. What is the maximum number of hi-fi systems Pierre can buy if he has $2000?

(a)
Discounted price of 1 hi-fi system in percent if only 1 was bought
= 100% - 15%
= 85%

100% of 1 hi-fi system = 500
1% of 1 hi-fi system = 500 ÷ 100 = 5
85% of 1 hi-fi system = 85 x 5 = 425 

Amount that Bryan paid for 1 hi-fi system = $425

(b)
Discounted price of 1 hi-fi system in percent if more than 1 was bought
= 100% - 20%
= 80%

80% of 1 hi-fi system = 80 x 5 = 400

Amount that Pierre paid for 1 hi-fi system = $400

Maximum number of hi-fi systems that Pierre can buy if he has $2000
= 2000 ÷ 400
= 5 r 0

Answer(s): (a) $425; (b) 5