A total of 900 pupils sat for the Social Studies mock test. ⁴₅ of the boys and ⁹₁₀ of the girls failed the mock test. The same number of girls and boys passed the mock test. How many more girls than boys failed the mock test?
Fraction of the boys that passed the mock test
= 1 - ⁴₅
= ¹₅

Fraction of the girls that passed the mock test
= 1 - ⁹₁₀
= ¹₁₀

Number of boys and girls that passed the mock test is the same. Make the numerators the same.
¹₅ Boys = ¹₁₀ Girls

Total number of boys = 5 u
Total number of girls = 10 u

Total number of pupils
= 5 u + 10 u
= 15 u

15 u = 900

1 u = 900 ÷ 15 = 60

Number of boys that failed the mock test = 4 u
Number of girls that failed the mock test = 9 u

Number of more girls than boys who failed the mock test
= 9 u - 4 u
= 5 u
= 5 x 60
= 300

Answer(s): 300