how do you solve proportions

Question

 idk how to solve proportions can i plz get some help

Answer 1

Set the proportions equal to each other and cross multiply.

 

For example, thee eatio of red to blue is 5:12. How many blues are there if there are 25 reds?

 

5/12 = 25/b

 

5b = 12(25)

5b = 300

b = 60

 

There are 60 blues.