The average age of a family of 5 members is 20 years. If the age of the…
2026
The average age of a family of 5 members is 20 years. If the age of the youngest member of the family is 5 years, then what was average age of the family at the time of birth of the youngest member?
Answer: C. 18.75 years — First, calculate the current total age of all 5 family members: 20 * 5 = 100 years. Since the youngest member is 5 years old, 5 years ago they were just born.…
- A.
20 years
- B.
18 years
- C.
18.75 years
- D.
19 years
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Correct answer: C
First, calculate the current total age of all 5 family members: 20 * 5 = 100 years.
Since the youngest member is 5 years old, 5 years ago they were just born.
Therefore, at that time, there were only 4 family members.
The sum of the ages of the other 4 members currently is 100 - 5 = 95 years.
Five years ago, each of these 4 members was 5 years younger. So their total age then was 95 - (4 * 5) = 75 years.
The average age of the family at that time was 75 / 4 = 18.75 years.