Multiple choice

The average age of a family of five members is 24. If the youngest member of the family is 8 years old, then find the average of the family at the time when the youngest member was born?

  1. 20

  2. 24

  3. 16

  4. 23

  5. 18
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Current total age of 5 members = 5 × 24 = 120 years. Youngest is 8 years old. When the youngest was born (8 years ago), the other 4 members were each 8 years younger. Their total age then was 120 - 8 - (4 × 8) = 80 years. Including the newborn (age 0), there were 5 family members. Average = 80 ÷ 5 = 16 years.

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