Question

The mean age of 12 boys is 8 year later it was found that the age of one boy was taken as 13 instead of 10 years . Find the actual mean of their ages.

Answer 1

Answer:

The actual mean of their Ages is 7.75

Step-by-step explanation:

Given :

• Mean of 12 boys' age = 8 years
• Wrong age taken = 13 instead of 10

To Find :

• The actual mean

Solution :

Mean of 12 boys' age is 8. Consider Sum of their ages as x

⟹ x/12 = 8

⟹ x = 12 × 8

⟹ x = 96

Sum of their Ages with wrong age is 96.

_________________________

Find the Difference between the wrong and Correct age.

⟹ 13 - 10

⟹ 3

__________________________

Subtract 3 from the sum of ages (96).

⟹ 96 - 3

⟹ 93

93 is the sum of the Ages with correct ages of all the boys.

__________________________

Calculate the mean

Sum of Observations = 93

Number of Observations = 12

⟹ 93/12

⟹ 7.75

.°. The actual mean of their Ages is 7.75

Answer 2

Answer:

7.75

Explation :

x/12 = 8

x= 12 × 8

x = 96

difference the ages :

13- 10

3

sum of ages :

93

96 - 3= 93

find the mean :

93/12

7.75

Therefore the answer is 7.75