GRIDDED RESPONSE Mark got 18 out of 25 questions correct on his science test. What percent
of the questions did he get correct?

72%

Step-by-step explanation:

A percentage is a number out of 100.  For example, 32/100 is 32%.  What you want to do with percentages is multiply the denominator of a fraction so it becomes 100 and multiply that same number to the numerator.  Sort of like a ratio!

If Mark got 18/25, we can multiply 25 by 4 to get 100 as the denominator.

Since you multiplied the denominator by 4, you have to multiply the numerator by 4 as well.  

18 times 4= 72.  So the numerator is 72 and the denominator is 100.  The fraction is 72/100, which is 72% since it is out of 100.