Question

A friend bought 2 boxes and 8 notebooks for school, it cost him $11 He went back to the store the same day to buy school supplies for his younger brother. He spent $11.25 on 3 boxes of pencils and 5 notebooks. How much would 7 notebooks cost?

Answer 1

$5.25

Explanation:

If the friend tripled the first purchase and subtracted twice the second purchase, he would have the cost of 3·8-2·5 = 14 notebooks. 7 notebooks would cost half that amount:

(3·$11 -2·11.25)/2 = $5.25 . . . . . cost of 7 notebooks