Question

( 370
The average age of a group of 13 boys is 13.
When two more boys joined the group, the
average rose by 2 years. The sum of the ages
of the two new boys is:
(A) 26
(B) 30
(C) 50
(D) 56​

Answer 1

(D) 56​

The sum of the ages of the two new boys is 56.

Explanation:

Formula :

Average = (Sum of observations) ÷ (Number of observations)

Sum of observations = Average x   (Number of observations)

Given: The average age of a group of 13 boys is 13.

Sum of ages of 13 boys = 13 x 13 =169

When two more boys joined the group, the average becomes 15 years

Sum of ages of 15 boys  =  15 x 15 =225

The sum of the ages of the two new boys = (Sum of ages of 15 boys) -(Sum of ages of 13 boys )

=225-169 =56

Hence, the sum of the ages of the two new boys is 56.

Thus , the correct answer is (D) 56​.

# Learn more :

The average age of A and B is 36 years, average age of B and C is 35 years. and average age of A and C is 29 years. what will be the age of A.

https://brainly.in/question/6273534