Recovering a deceased member’s income from changing family averages: The average monthly income of 4 earning members of a family is ₹7350. After one member passes away, the average monthly income becomes ₹6500 for the remaining 3 members. What was the monthly income of the member who passed away?
Correct Answer: ₹ 9900
Introduction / Context:Averages convert to totals seamlessly. With the original four-member average and the new three-member average, we can find the lost member’s contribution as the difference between totals.
Given Data / Assumptions:
- 4-member average = ₹7350 → total = ₹29400
- 3-member average = ₹6500 → total = ₹19500
Concept / Approach:Income of the deceased = original total − new total.
Step-by-Step Solution:Original total = 4 * 7350 = ₹29400New total = 3 * 6500 = ₹19500Missing income = ₹29400 − ₹19500 = ₹9900
Verification / Alternative check:Re-add ₹9900 to the remaining totals: (₹19500 + ₹9900) / 4 = ₹29400 / 4 = ₹7350, consistent.
Why Other Options Are Wrong:Other values do not reconcile the two totals to the given averages.
Common Pitfalls:Mistaking an average change as a per-person change; always work with totals first.
Final Answer:₹ 9900