Sam can solve 30 multiplication problems in 2 minutes how many can he solve in 20 minutes

Hi there!
The question here gives us that Sam can solve 30 multiplication problems in 2 minutes, and we are asked to solve it in 20 minutes. There are many ways to get the answer, but I'll be showing you the easiest method.
Let the number of problems Sam solves in 20 minutes be represented by x
First, write the given information.
30 problems = 2 minutes
x problems = 20 minutes
We can rewrite the given information like this - 

Use cross multiplication to simplify further - 

Divide both sides by 2 - 

Therefore, Sam can do 300 problems in 20 minutes. Hope this helped!