According to question ,
Total age of three youngsters = 33 × 3 – 11 × 3
Total age of three youngsters = 99 – 33 = 66 years

Correct Option: C

According to question ,
Total age of three youngsters = 33 × 3 – 11 × 3
Total age of three youngsters = 99 – 33 = 66 years
∴ Required average = 66 ÷ 3 = 22 years

Given that , Age of C = 8 years
The average age of four boys A, B, C and D = 5 years
⇒ A + B + C + D = 20 years
⇒ A + B + D = 20 – 8 = 12 years
∴ The average age of A, B, D, E = 6 years.

Correct Option: A

Given that , The average age of A, B, D, E = 6 years.
Age of C = 8 years
The average age of four boys A, B, C and D = 5 years
⇒ A + B + C + D = 20 years
⇒ A + B + D = 20 – 8 = 12 years
∴ The average age of A, B, D, E = 6 years.
Now, A + B + D + E = 24 years
∴ E = 24 – 12 = 12 years

Given that , Two years ago , the average age of a family of 8 members = 18 years
After the addition of a baby, the average age of the family is same today.
Sum of present ages of 9 member family = 18 × 9 = 162 years
Sum of 8 member’s present ages = 18 × 8 + 2 × 8 = 144 + 16 = 160 years

Correct Option: A

Given that , Two years ago , the average age of a family of 8 members = 18 years
After the addition of a baby, the average age of the family is same today.
Sum of present ages of 9 member family = 18 × 9 = 162 years
Sum of 8 member’s present ages = 18 × 8 + 2 × 8 = 144 + 16 = 160 years
∴ Child’s age = 162 – 160 = 2 years

Here , Age of the youngest member = 9 years
In a family of 5 members, the average age at present = 33 years.
Sum of the present age of family members = 33 × 5 = 165 years
9 years ago,
Sum of their age = 165 – 9 × 5 = 120 years

Correct Option: A

Here , Age of the youngest member = 9 years
In a family of 5 members, the average age at present = 33 years.
Sum of the present age of family members = 33 × 5 = 165 years
9 years ago,
Sum of their age = 165 – 9 × 5 = 120 years
∴ Required average age = 120 ÷ 4 = 30 years

According to question ,
The average age is reduced by 3 years.
∴ Age of the retired teacher = 25 + 3 × 10

Correct Option: D

According to question ,
The average age is reduced by 3 years.
∴ Age of the retired teacher = 25 + 3 × 10
Age of the retired teacher = 55 years