In a class, there are 18 boys who are over 160 cm tall. If these constitute three-fourths of the boys and the total number of boys is two-thirds of the total number of students in the class, what is the number of girls in the class?

Options

A. 6
B. 12
C. 18
D. 24

Answer

B

Explanation

Let the number of boys = x and the total number of students = y
Then, the number of girls = (y - x).
According to the question
`3/4 x = 18 ... (i) `
`2/3 y = 24 ...(ii)`
Solving (i) & (ii) independently, we get
`x = (18 xx 4)/3 = 24`
`y = (24 xx 3)/2 = 36`
So, Number of girls in the class = `(y - x) `
`= (36 - 24) = 12 `