Question

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 ?

• A. 6
• B. 12
• C. 18
• D. 24

Answer 1

Answer: (B)

12

Answer 2

Let the number of boys in the class be $b$.
According to the question,
$\frac 23 b = 18$
$b = 24$
Let the total number of students in the class be $t$.
According to the question,
$\frac 23t = 24$
$t = 36$
Total number of students in class $= 36$
Number of girls in the class $= 36 - 24 = 12$

So, the correct option is (B) : 12.