PSLE
In a school, 40% of the members in Drama Club and 75% of the members in Reading Club are boys. Both clubs have the same number of girls. The Drama Club has 70 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	2x1	3x1	3x3	1x3
Comparing the girls in 2 clubs		1		1
	2 u	3 u	9 u	3 u

40% = ⁴⁰₁₀₀ = ²₅

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

75% = ⁷⁵₁₀₀ = ³₄

Fraction of the members in Reading club that are girls
= 1 - ³₄
= ¹₄

The number of girls in both clubs is the same. Make the numerators the same. LCM of 3 and 1 is 3. 

3x15x1 of the members in Drama Club = 1x34x3 of the members in Reading Club
35of the members in Drama Club = 312 of the members in Reading Club

Number of less boys in Drama Club than Reading Club
= 9 u - 2 u
= 7 u

7 u = 70

1 u = 70 ÷ 7 = 10

Number of members in Reading Club
= 12 u
= 12 x 10
= 120

Answer(s): 120