Question

In a class.the average age of 40 boys is 13.5 years & that of the girl is 13years.the average age of the whole class is 13.4 years.Find the number of girls in the class?

Answer 1

Answer:

5*13/4

65/4

13 approx

I hope I understand

Answer 2

Answer:

10

Step-by-step explanation:

There are 40 boys in the class with average age 13.5 years.

Assume that there are x girls in the class with average age 13 years.

If the average age of the whole class is 13.4 years, then we can write the equation

$\frac{(40*13.5)+13x}{40+x} =13.4$

⇒540+13x=536+13.4x

⇒ 0.4x=4

⇒ x= 10.

Therefore, there are 10 girls in the class. (Answer)