Question

Two customers went to the post office to buy postcards and large envelopes. Each postcard costs the same amount and each large envelope costs the same amount.

● The first customer paid $12 for 14 postcards and 5 large envelopes.


● The second customer paid $24.80 for 10 postcards and 15 large envelopes.



What was the cost in dollars of each large envelope?




1. $1.42

2. $1.15

3. $0.63

Answer 1

The first one $1.42

Explanation:

1.42x5=7.1 (cost of all envelopes)

12-7.1=4.9

4.9/14=0.35 (one postcard)

10 postcards= 3.5

1.42x15=21.3 (cost of all envelopes)

3.5+21.3=$24.80