Mathematics: It cost maria 20 cents to mail a postcard and 33 cents to mail a letter. she sent either a postcard or a letter to each of 18 people and spent $4.38. let x represent the number of postcards she wrote. what would be the expression for the number of letters? how many postcards did maria send?

It cost maria 20 cents to mail a postcard and 33

AptAlbatross

13.03.2022

The the expression for the number of letters = 18-x

Maria sent 12 postcards

Step-by-step explanation:

Given : Cost of mail a postcard =20 cents

Cost of mail a letter = 33 cents

Since 1 dollar = 100 cents

Total money spent by Maria = $\$4.38=438\text{ cents}$

Let x represent the number of postcards she wrote.

The the expression for the number of letters = 18-x

According to the question we have ,

$20x+33(18-x)=438\\\\\Rightarrow\ 20x+594-33x=438\\\\\Rightarrow\ 20x-33x=438-594\\\\\Rightarrow\ -13x=-156\\\\\Rightarrow\ x=\dfrac{156}{13}=12$

Hence, Maria sent 12 postcards and 6 letters .

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