Lee and Simon went to buy hi-fi systems at a sale. The usual price of 1 hi-fi system was $1500 each.

SALE
Buy 1 hi-fi system at 5% discount
Buy 2 or more hi-fi systems at 10% discount each

1. Lee bought 1 hi-fi system. How much did he pay?
2. What is the maximum number of hi-fi systems Simon can buy if he has $4000?

(a)
Discounted price of 1 hi-fi system in percent if only 1 was bought
= 100% - 5%
= 95%

100% of 1 hi-fi system = 1500
1% of 1 hi-fi system = 1500 ÷ 100 = 15
95% of 1 hi-fi system = 95 x 15 = 1425 

Amount that Lee paid for 1 hi-fi system = $1425

(b)
Discounted price of 1 hi-fi system in percent if more than 1 was bought
= 100% - 10%
= 90%

90% of 1 hi-fi system = 90 x 15 = 1350

Amount that Simon paid for 1 hi-fi system = $1350

Maximum number of hi-fi systems that Simon can buy if he has $4000
= 4000 ÷ 1350
= 2 r 1300

Answer(s): (a) $1425; (b) 2