PSLE
In a school, 30% of the members in Chess Club and 50% of the members in Literary Club are boys. Both clubs have the same number of girls. The Literary Club has 8 more boys than the Chess Club. How many boys are there altogether?

	Chess Club		Literary 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 Chess Club that are girls
= 1 - ³₁₀
= ⁷₁₀

50% = ⁵⁰₁₀₀ = ¹₂

Fraction of the members in Literary 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 Chess Club = 1x72x7 of the members in Literary Club
710of the members in Chess Club = 714 of the members in Literary Club

Number of more boys in Literary Club than Chess Club
= 7 u - 3 u
= 4 u

4 u = 8

1 u = 8 ÷ 4 = 2

Total number of boys
= 3 u + 7 u
= 10 u
= 10 x 2
= 20

Answer(s): 20