Question

Four boys average age are 15 years and three boys average age are 12 years then find the age of fourth boy ?

Answer 1

sorry my dear friend... I really can't understand this question.....

Answer 2

Average =
$\frac{sum \: of \: quatities}{no. \: quanities}$
Here,

Average of 4 boys = (sum of 4 age)/4

15 =(sum of 4 ages) /4

15*4 =sum of 4 ages.

60 =sum of 4 ages

==================

Average of 3 boys ={sum of 4 age - 1 age)/3

12 = (60-age of fourth boy) /3

12*3 = 60- age of fourth boy

36 = 60- age of fourth boy

60-36 = age of fourth boy

24 = age of fourth boy



I hope this will help you


-by ABHAY