15%+25%=40%, meaning that 40% of the class didn’t get a perfect score and 60% did. If 24 students got a perfect score and 24 students is equal to 60% of the class, you can solve by setting up a proportion.
24 students X students
——————- = —————-
60% of class 100% of class
Next, cross multiply to get 2400 = 60X. Divide both sides by 60 and you’ll get 40. There are 40 students in the class.
