### Home > CAAC > Chapter 4 > Lesson 4.1.5 > Problem4-48

4-48.

Mr. Wallis decided to create another table to figure out how much it costs to send a certain number of regular letters through the mail. Use proportional reasoning to complete his table below. 4-48 HW eTool (Desmos). Homework Help ✎

 Number of Letters Cost of Stamps 10 $3.40 2$0.68 $5.10 7 1 500$14.28

First set up the proportion.

$\frac{2}{0.68}=\frac{n}{5.10}$

What did you multiply 0.68 by to get 5.10?

7.5

15 letters for \$5.10

Multiply 2 by 7.5 to get the number of letters. Repeat this strategy for all of the blanks within the table.