PSLE
In a school, 30% of the members in Chess Club and 45% of the members in Literary Club are girls. Both clubs have the same number of boys. The Literary Club has 60 more girls than the Chess Club. How many girls are there altogether?

	Chess Club		Literary Club
Types	Girls	Boys	Girls	Boys
Comparing the girls and the boys in each club	3x11	7x11	9x7	11x7
Comparing the boys in 2 clubs		1		1
	33 u	77 u	63 u	77 u

30% = ³⁰₁₀₀ = ³₁₀

Fraction of the members in Chess Club that are boys
= 1 - ³₁₀
= ⁷₁₀

45% = ⁴⁵₁₀₀ = ⁹₂₀

Fraction of the members in Literary club that are boys
= 1 - ⁹₂₀
= ¹¹₂₀

The number of boys in both clubs is the same. Make the numerators the same. LCM of 7 and 11 is 77. 

7x1110x11 of the members in Chess Club = 11x720x7 of the members in Literary Club
77110of the members in Chess Club = 77140 of the members in Literary Club

Number of more girls in Literary Club than Chess Club
= 63 u - 33 u
= 30 u

30 u = 60

1 u = 60 ÷ 30 = 2

Total number of girls
= 33 u + 63 u
= 96 u
= 96 x 2
= 192

Answer(s): 192