The average age of Ram's family of 6 members is 22 years. If the age of the…
2024
The average age of Ram's family of 6 members is 22 years. If the age of the youngest member be 7 years, the average age of the family at the birth of the youngest member was
- A.
36 years
- B.
38 years
- C.
32 years
- D.
18 years
Attempted by 44 students.
Show answer & explanation
Correct answer: D
Total current age of the family = 22 × 6 = 132.
Current age of the youngest = 7. Sum of the other five members now = 132 − 7 = 125.
At the birth of the youngest (7 years ago) each of those five was 7 years younger, so their total then = 125 − 5 × 7 = 90.
Average age at that time (for the five older members) = 90 ÷ 5 = 18 years.
Note: If one instead included the newborn (counting six members at birth), the average would be (132 − 6 × 7) ÷ 6 = 15, but the standard interpretation here is the average of the other family members at the birth, which gives 18.