A quarter of the learners in a class have blond hair and two thirds have brown hair. The rest of the

A quarter of the learners in a class have blond hair and two thirds have brown hair. The rest of the learners in the class have black hair. How many learners in the class if 9 of them have blonde hair?

Total learners = Blond + Brown + Black

Total Learners = 1/4 + 2/3 + Black

Total Learners will be 1, the sum of all fractions
1/4 + 2/3 + Black = 1

Using common denominators of 12, we have:
3/12 + 8/12 + Black = 12/12
11/12 + Black = 12/12

Subtract 11/12 from each side:
Black = 1/12

Let t be the total number of people in class. We are given for blondes:
1/4t = 9

Multiply each side by 4
t = 36

Brown Hair
2/3(36) = 24

Black Hair
1/12(36) = 3