Question

José collects stamps. He has 7 used stamps for every 4 new stamps. If he has 28 new stamps, how many used stamps does he have?

I want to learn how to solve these type of problems

Answer 1

Answer:

José has 49 used stamps

Step-by-step explanation:

7 used stamps for every 4 new stamps

To solve this type of problem, we can use a ratio

7 : 4 ratio

He has 28 new stamps

7 : 4 = x : 28

Ratios can be written as fractions

$\frac{7}{4} = \frac{x}{28}$

Cross multiply

4x = 7(28) = 196

Divide by 4 on both sides

x = 49

Hope this helps :)