Andy and Luke went to buy hi-fi systems at a sale. The usual price of 1 hi-fi system was $700 each.

SALE
Buy 1 hi-fi system at 20% discount
Buy 2 or more hi-fi systems at 35% discount each

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

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

100% of 1 hi-fi system = 700
1% of 1 hi-fi system = 700 ÷ 100 = 7
80% of 1 hi-fi system = 80 x 7 = 560 

Amount that Andy paid for 1 hi-fi system = $560

(b)
Discounted price of 1 hi-fi system in percent if more than 1 was bought
= 100% - 35%
= 65%

65% of 1 hi-fi system = 65 x 7 = 455

Amount that Luke paid for 1 hi-fi system = $455

Maximum number of hi-fi systems that Luke can buy if he has $2000
= 2000 ÷ 455
= 4 r 180

Answer(s): (a) $560; (b) 4