Cole and Sam went to buy stereo systems at a sale. The usual price of 1 stereo system was $1600 each.

SALE
Buy 1 stereo system at 15% discount
Buy 2 or more stereo systems at 20% discount each

1. Cole bought 1 stereo system. How much did he pay?
2. What is the maximum number of stereo systems Sam can buy if he has $6000?

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

100% of 1 stereo system = 1600
1% of 1 stereo system = 1600 ÷ 100 = 16
85% of 1 stereo system = 85 x 16 = 1360 

Amount that Cole paid for 1 stereo system = $1360

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

80% of 1 stereo system = 80 x 16 = 1280

Amount that Sam paid for 1 stereo system = $1280

Maximum number of stereo systems that Sam can buy if he has $6000
= 6000 ÷ 1280
= 4 r 880

Answer(s): (a) $1360; (b) 4