Seth and George went to buy mobile phones at a sale. The usual price of 1 mobile phone was $1500 each.

SALE
Buy 1 mobile phone at 15% discount
Buy 2 or more mobile phones at 20% discount each

1. Seth bought 1 mobile phone. How much did he pay?
2. What is the maximum number of mobile phones George can buy if he has $8000?

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

100% of 1 mobile phone = 1500
1% of 1 mobile phone = 1500 ÷ 100 = 15
85% of 1 mobile phone = 85 x 15 = 1275 

Amount that Seth paid for 1 mobile phone = $1275

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

80% of 1 mobile phone = 80 x 15 = 1200

Amount that George paid for 1 mobile phone = $1200

Maximum number of mobile phones that George can buy if he has $8000
= 8000 ÷ 1200
= 6 r 800

Answer(s): (a) $1275; (b) 6