Two customers went to a post office to buy postcards and large envelopes. each postcards 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?

$1.42 is the cost of each large envelope.

Step-by-step explanation:

Let x represents the cost of one postcards and y represents the cost of one large envelope.

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

That is, 14 x + 5 y = 12         (1)

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

That is, 10 x + 15 y = 24.80  (2)

3 × equation (1),

We get, 42 x + 15 y = 36 (3)

Equation (3) - Equation (2)

32 x = 11.20

⇒ x = 11.20/32

⇒ x = 0.35

By putting the value of x in equation (1),

We get, 14 × 0.35 + 5 y = 12

⇒ 4.9 + 5 y = 12

⇒ 5 y = 7.1

⇒ y = 1.42

Thus, the cost of one postcard = $ 0.35

And, the cost of each large envelope = $ 1.42

1.42

Step-by-step explanation:

got this question right!

answer: 12

step-by-step explanation: