PSLE
In a school, 30% of the members in Fitness Club and 50% of the members in Reading Club are boys. Both clubs have the same number of girls. The Reading Club has 12 more boys than the Fitness Club. How many boys are there altogether?

	Fitness Club		Reading Club
Types	Boys	Girls	Boys	Girls
Comparing the boys and the girls in each club	3x1	7x1	1x7	1x7
Comparing the girls in 2 clubs		1		1
	3 u	7 u	7 u	7 u

30% = ³⁰₁₀₀ = ³₁₀

Fraction of the members in Fitness Club that are girls
= 1 - ³₁₀
= ⁷₁₀

50% = ⁵⁰₁₀₀ = ¹₂

Fraction of the members in Reading club that are girls
= 1 - ¹₂
= ¹₂

The number of girls in both clubs is the same. Make the numerators the same. LCM of 7 and 1 is 7. 

7x110x1 of the members in Fitness Club = 1x72x7 of the members in Reading Club
710of the members in Fitness Club = 714 of the members in Reading Club

Number of more boys in Reading Club than Fitness Club
= 7 u - 3 u
= 4 u

4 u = 12

1 u = 12 ÷ 4 = 3

Total number of boys
= 3 u + 7 u
= 10 u
= 10 x 3
= 30

Answer(s): 30