There are 4 boys in a class of 13 students.

(a) What is the ratio of girls to boys?

(b) What is the ratio of girls to all students in the class?

8

X

5

?

(a) = 9:4

(b) = 9:13

8x5=40

A - 9:4

B - 9:13

8*5=40

To find girls, you need to subtract boys (4) from total (13).

You get 9, so that is girls. 9 girls to 4 boys. Total is 13 so 9 girls to 13 people total. For the last one, if you are asking 8*5, that is 40.