PSLE
In a school, 30% of the members in Reading Club and 40% of the members in Drama Club are boys. Both clubs have the same number of girls. The Reading Club has 20 less boys than the Drama Club. How many members are there in Drama Club?

	Reading Club		Drama Club
Types	Boys	Girls	Boys	Girls
Comparing the boys and the girls in each club	3x3	7x3	2x7	3x7
Comparing the girls in 2 clubs		1		1
	9 u	21 u	14 u	21 u

30% = ³⁰₁₀₀ = ³₁₀

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

40% = ⁴⁰₁₀₀ = ²₅

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

The number of girls in both clubs is the same. Make the numerators the same. LCM of 7 and 3 is 21. 

7x310x3 of the members in Reading Club = 3x75x7 of the members in Drama Club
2130of the members in Reading Club = 2135 of the members in Drama Club

Number of less boys in Reading Club than Drama Club
= 14 u - 9 u
= 5 u

5 u = 20

1 u = 20 ÷ 5 = 4

Number of members in Drama Club
= 35 u
= 35 x 4
= 140

Answer(s): 140