Pierre and Oliver went to buy projectors at a sale. The usual price of 1 projector was $1400 each.

SALE
Buy 1 projector at 10% discount
Buy 2 or more projectors at 15% discount each

1. Pierre bought 1 projector. How much did he pay?
2. What is the maximum number of projectors Oliver can buy if he has $3000?

(a)
Discounted price of 1 projector in percent if only 1 was bought
= 100% - 10%
= 90%

100% of 1 projector = 1400
1% of 1 projector = 1400 ÷ 100 = 14
90% of 1 projector = 90 x 14 = 1260 

Amount that Pierre paid for 1 projector = $1260

(b)
Discounted price of 1 projector in percent if more than 1 was bought
= 100% - 15%
= 85%

85% of 1 projector = 85 x 14 = 1190

Amount that Oliver paid for 1 projector = $1190

Maximum number of projectors that Oliver can buy if he has $3000
= 3000 ÷ 1190
= 2 r 620

Answer(s): (a) $1260; (b) 2