Question

the mean age of five boys is 26 years . if the age of 4 of them be 15,18,14 and 19yrs then find the age of fifth ​

Answer 1

Answer:

64 years

Step-by-step explanation:

Given,

mean age of '5' boys is 26 years

Age of '4' of them = 15 , 18 , 14 , 19 yrs

To Find :-

Age of the '5' th boy

How To Do :-

We know that 'Mean = Sum of observation/ Number of observations' , So we need to equate the mean to the sum of the ages of the boys divided by number of boys and we need to put the values of ages of '4' boys and we need to find the age of '5th' boy.

Formula Required :-

$Mean=\dfrac{Sum\:of\:observations}{Number\:of\:observations}$

Solution :-

Let , the age of the 5th boy be 'x' yrs

Sum of the ages of the boys = 15 + 18 + 14 + 19 + x

= 33 + 33 + x

= 66 + x

Number of boys = 5

Given , Mean = 26 years

$\implies 26=\dfrac{66+x}{5}$

26 × 5 = 66 + x

130 = 66 + x

x = 130 - 66

x = 64

∴ Age of the 5th boy = x = 64 years