Salman, Ambani, and Dalmiya together have an average of 60 shirts. If each buys 6 more shirts, what is the new average number of shirts per person?
Aptitude
Average
Difficulty: Easy
Choose an option
Answer
Correct Answer: 66
Explanation
Introduction / Context:When each member of a group adds the same quantity, the group average increases by that quantity as well. This property saves time over recomputing totals from scratch.
Given Data / Assumptions:
- Initial average shirts per person = 60
- Three people
- Each buys 6 more shirts
Concept / Approach:If everyone adds the same number x, the average increases by x. No need to know individual counts to find the new mean.
Step-by-Step Solution:
Initial average = 60 Increase per person = 6 New average = 60 + 6 = 66Verification / Alternative check:Total initially = 60 * 3 = 180. Added total = 6 * 3 = 18. New total = 198. New average = 198 / 3 = 66. Confirms the shortcut.
Why Other Options Are Wrong:
- 63 and 62: Do not reflect the full +6 change per person.
- can't be determined: The rule permits determination without individual breakdowns.
- None of these: A correct exact value exists (66).
Common Pitfalls:Adding 6 only once to the total instead of per person, which would understate the increase in the mean.
Final Answer:66