In a class, 18 children are girls.

Question

A quarter of the children are boys.

Altogether, how many children are there in the class?

Answer 1

number is the whole class ---- x
number of boys = x-18
or
number of boys = (1/4)x

x/4 = x-18
times 4
x = 4x - 72
-3x=-72
x = 24

state your conclusion

Answer 2

if 1/4 are boys, the 18 girls make up 3/4 of the class.

18 = 3/4 * 24