The average mark of 60 students in a class is 62. The average marks of boys and girls in that subject are 60 and 65, respectively. The number of boys in the class is:
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. 36.
Let the number of boys be x and girls be y.
According to the question;
⇒ (x + y) × 62 = 60x + 65y
⇒ 62x + 62y = 60x + 65y
⇒ x/y = 3/2
Let the ratio be 3n and 2n
Total number of boys and girls = 60
⇒ 3n + 2n = 60
⇒ 5n = 60
⇒ n = 12
Total number of boys = 3 × 12 = 36