# Ms. Burger has graded 45 tests. This represents 60% of her 3 math classes. How many math students does Ms. Burger teach?

##### 1 Answer

We assume that the

So, we have the equation:

#0.60s = 45#

where

Note that

That means the total number of students (not distinguishing between the number of students per class) is:

#color(blue)(s) = 45/0.60 = color(blue)(75)#

(we divided both sides by#0.60# )

**NOTE:** *A common mistake is to write:*

#s = 0.60xx45# ,

*which is backwards. It would say that there were more tests given out than students who took the test. Make sure your answer makes physical sense.*