Ryan and Ahmad went to buy hard drives at a sale. The usual price of 1 hard drive was $1700 each.

SALE
Buy 1 hard drive at 15% discount
Buy 2 or more hard drives at 20% discount each

1. Ryan bought 1 hard drive. How much did he pay?
2. What is the maximum number of hard drives Ahmad can buy if he has $4000?

(a)
Discounted price of 1 hard drive in percent if only 1 was bought
= 100% - 15%
= 85%

100% of 1 hard drive = 1700
1% of 1 hard drive = 1700 ÷ 100 = 17
85% of 1 hard drive = 85 x 17 = 1445 

Amount that Ryan paid for 1 hard drive = $1445

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

80% of 1 hard drive = 80 x 17 = 1360

Amount that Ahmad paid for 1 hard drive = $1360

Maximum number of hard drives that Ahmad can buy if he has $4000
= 4000 ÷ 1360
= 2 r 1280

Answer(s): (a) $1445; (b) 2