Question

Kendra sold 50 boxes of cookies in 20 days. Her older sister, Alecia, sold twice as many boxes in half as many days. If the two girls continued at the same sales rates, how many total boxes would both girls have sold if they had both sold cookies for 40 days?

Answer 1

in 40 days Kendra will have sold 100 boxes and her sister sold 160

Explanation:

set up proportions for each sister

Kendra: 50/20 = b/40 cross-multiply to get 20b = 200

Alecia: 40/10 = b/40 cross-multiply to get 10b = 1600

Answer 2

Alecia would have sold 400 boxes.

Kendra would have sold 100 boxes.

Explanation:

First we have to find the unit rate of each girl's cookie sale.

Kendra: 50 ÷ 20 = 2.5

This mean Kendra sold 2.5 cookies each day.

If Alecia sold twice as many boxes, that would be 100 boxes. And if it was in half amount of days, that would be 10 days.

Alecia sold 100 boxes in 10 days.

100 ÷ 10 = 10

She sold 10 boxes each day.

Alecia: 10 × 40 = 400

Kendra: 2.5 × 40 = 100