How much will 30 pencils cost if 10 pencils cost $0.59 and there is a $0.10 discount if your purchase 3 dozen?

we know 10 pencils cost 0.59, that means that 1 pencil alone costs 0.59 ÷ 10 = 0.059, close to 6 pennies really for each one.

well, the discount only occurs if we purchase 3 dozens, namely 36 pencils, however we're only buying 30, so no discount, all pencils are at regular price, namely 30 * 0.059 = 1.77.

the answer is y = 11.54

hope this : )