PSLE
In a school, 40% of the members in Drama Club and 60% of the members in Reading Club are boys. Both clubs have the same number of girls. The Drama Club has 20 less boys than the Reading Club. How many members are there in Reading Club?

	Drama Club		Reading Club
Types	Boys	Girls	Boys	Girls
Comparing the boys and the girls in each club	2x2	3x2	3x3	2x3
Comparing the girls in 2 clubs		1		1
	4 u	6 u	9 u	6 u

40% = ⁴⁰₁₀₀ = ²₅

Fraction of the members in Drama Club that are girls
= 1 - ²₅
= ³₅

60% = ⁶⁰₁₀₀ = ³₅

Fraction of the members in Reading club that are girls
= 1 - ³₅
= ²₅

The number of girls in both clubs is the same. Make the numerators the same. LCM of 3 and 2 is 6. 

3x25x2 of the members in Drama Club = 2x35x3 of the members in Reading Club
610of the members in Drama Club = 615 of the members in Reading Club

Number of less boys in Drama Club than Reading Club
= 9 u - 4 u
= 5 u

5 u = 20

1 u = 20 ÷ 5 = 4

Number of members in Reading Club
= 15 u
= 15 x 4
= 60

Answer(s): 60