How do you get answer for 4/5% of 500 equals what?

In a class, there are 12 girls. if the ratio of boys to girls is 5: 4 how many boys are there in the class

Adecorative window is made up of a rectangle with semicircles at either end. the ratio of ad to ab is 3: 2 and ab is 30 inches. what is the ratio of the area of the rectangle to the combined area of the semicircles? possible answers: a. 2: 3 b. 3: 2 c. 6: π d. 9: π e. 30: π

How many verticies does a triangular prims have