PSLE
In a school, 30% of the members in Art Club and 50% of the members in Computer Club are boys. Both clubs have the same number of girls. The Computer Club has 16 more boys than the Art Club. How many boys are there altogether?

	Art Club		Computer 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 Art Club that are girls
= 1 - ³₁₀
= ⁷₁₀

50% = ⁵⁰₁₀₀ = ¹₂

Fraction of the members in Computer 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 Art Club = 1x72x7 of the members in Computer Club
710of the members in Art Club = 714 of the members in Computer Club

Number of more boys in Computer Club than Art Club
= 7 u - 3 u
= 4 u

4 u = 16

1 u = 16 ÷ 4 = 4

Total number of boys
= 3 u + 7 u
= 10 u
= 10 x 4
= 40

Answer(s): 40