Two customers went to a post office to buy postcards and envelopes. each postcard costs the same amount, and each large envelope costs the same amount. the first customer paid $12 for 34 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 envelpoe

The cost of postcard is $0.122 and the cost of large envelope is $1.57.

Step-by-step explanation:

Let, the cost of postcards = x and the cost of large envelopes = y.

According to the question, we get the following system of equations,

34x + 5y = 12

10x + 15y = 24.80

We will now solve this system to obtain the value of x and y.

First, we divide second equation by 5,

34x + 5y = 12

2x + 3y = 4.96

Now, we multiply second equation by 17,

34x + 5y = 12

34x + 51y = 84.32

Subtracting the equations gives us,

-46y = -72.32 i.e. y = 1.57.

Substituting the vale of y in the first equation gives us,

34x + 5 × 1.57 = 12 i.e. 34x + 7.85= 12 i.e. 34x = 4.15 i.e. x = 0.122.

Hence, the cost of postcard is $0.122 and the cost of large envelope is $1.57.

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step-by-step explanation: