Question

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?

Answer 1

Answer: The the expression for the number of letters =
`18-x`

Maria sent 12 postcards

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=(156)/(13)=12`

Hence, Maria sent 12 postcards and 6 letters .