Question

the average age of three brothers is 15 year if the age of two brothers are 15 and 12 year find age of the third brothers class 5​

Answer 1

Step-by-step explanation:

let the ages of all the three brothers be A, B and C respectively,

then according to the question, we have

(A+B+C)/3 = 15,

A+B+C=15×3,

A+B+C=45,eq(1),

given

A=15 yrs,

B=12 yrs,

therefore

from eq(1), we get

15+12+C=45,

27+C=45,

then

C=45-27,

C=18 yrs

Answer 2

Answer:

Average = Sum of all number/No.of numbers

15 =$\frac{15 + 12 + x}{3}$

15 = $\frac{27 + x}{3}$

15 $\times$ 3 = 27 + $x$

45 - 27 = x

x = 18

Therefore, the age of the third brother is 18 years.