Question

average age of 3 brother is 15 years if the age of two brother is 15 years and 12 years find the age of the third brother

Answer 1

Let the total age of brothers be 'y'
Let the age of 3rd brother be 'x'
ATQ
15 = y/3
y = 45 years

Total age = 45 years
15 + 12 + x = 45
27 + x = 45
x = 18 years
Age of the 3rd brother is 18 years.

Answer 2

The age of the third brother  is 18 years.

Explanation:

It is given that,

The average age of 3 brother is 15 years.

Age of brother 1, $x_1=15\ yrs$

Age of brother 2, $x_2=12\ yrs$

We need to find the age of the third brother. The average of three numbers is given by :

$A=\dfrac{x_1+x_2+x_3}{3}$

$15=\dfrac{15+12+x_3}{3}$

On solving, $x_3=18\ yrs$

So, the age of the third brother  is 18 years. Hence, this is the required solution.

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