Two customers went to a 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?
a $1.42 c $1.15
b $0.35 d $0.63