Question

Sam is doing his math homework. Hey completes 10 probelms every 30 minutes. How many porbelms can sam complete in 60 minutes?

Answer 1

He can complete 20 problems in 60 minutes

Answer 2

Put the ratios into fraction form. Since you do not know how many problems, replace it with an unknown number a.k.a. a variable.

10/30 = x/60

Since you can get 30 to 60 by multiplying by 2, multiply everything on the left side by 2.

Then, you get 20/60, which means 20 = x. So, he can complete 20 minutes an hour.