Question

In 1990 it would have cost $3.70 to send 13 postcards and 7 letters. It would have cost
$2.65 to send 6 postcards and 7 letters. How much did it cost to send a letter in 1990?

Answer 1

Answer:

$0.37

Step-by-step explanation:

This can be solved by solving a system of linear equations that is shown above.