Question

Assertion (A): When the mean age of 20 children is 10 years and the mean age of 10 other children is 13 years, then the mean age of 30 children is 11 years.

Reason (R): Mean of 30 children = `"Total age of 20 + Total age of 10"/30`

Options

• Both A and R are true and R is the correct reason for A.

• Both A and R are true but R is the incorrect reason for A.

• A is true but R is false.

• A is false but R is true.

Answer 1

Both A and R are true and R is the correct reason for A.

Explanation:

Given:

Mean age of 20 children = 10 years

Mean age of 10 other children = 13 years

Calculate total ages:

Total age of 20 children = 20 × 10 = 200

Total age of 10 children = 10 × 13 = 130

Calculate the combined mean:

Mean of 30 children = `"Total age of 20 + Total age of 10"/30`

= `(200 + 130)/30`

= `330/30`

= 11