Respuesta :

Americ
x= total number of problems

This is a proportion problem.  80% is to 100% as 32 problems is to x problems.

80/100=32/x
Cross multiply
(80*x)=(100*32)
80x=3200
Divide both sides by 80
x=40

There were 40 questions on the test.

Hope this helps!  :)