Family average back in time: A family of five has present average 24 years (total 120). The youngest is 8 now. What was the family’s average age at the time of the youngest’s birth?

Introduction / Context:
To roll ages back 8 years, subtract 8 from everyone who existed then, and set the youngest to 0 at birth. Then recompute the average.

Given Data / Assumptions:

• Current family size = 5; current average = 24 ⇒ total = 120.
• Youngest is 8 years old now.

Concept / Approach:
8 years ago: each of the other 4 members was 8 years younger (−32 total). The youngest was a newborn (−8 more compared to now). Past total = 120 − 32 − 8.

Step-by-Step Solution:

Verification / Alternative check:

Why Other Options Are Wrong:

• 20, 12, 18 do not result from the correct total adjustment.

Common Pitfalls:

• Subtracting 8 only once instead of from each of the other 4 people.

Final Answer:
16 yr