The average weight of 30 Students is 25. If the Heaviest and Lightest are…
2025
The average weight of 30 Students is 25. If the Heaviest and Lightest are excluded the average weight reduces by 2. If only the Heaviest is excluded then also the average reduces by 2. What is the weight of the Lightest?
- A.
20
- B.
32
- C.
23
- D.
33
Show answer & explanation
Correct answer: C
Concept: When specific members of a group are removed, use Total = Average × Count. The combined weight of the removed members equals the original total minus the new total computed from the reduced count and the new average.
Original total weight of all 30 students = 30 × 25 = 750.
Excluding only the heaviest student leaves 29 students whose average is 25 − 2 = 23, so their total weight = 29 × 23 = 667.
The heaviest student's weight = 750 − 667 = 83.
Excluding both the heaviest and the lightest student leaves 28 students whose average is also 25 − 2 = 23, so their total weight = 28 × 23 = 644.
The combined weight of the heaviest and lightest students = 750 − 644 = 106.
The lightest student's weight = 106 − 83 = 23.
Cross-check: with the heaviest at 83 and the lightest at 23, the remaining 28 students carry 750 − 83 − 23 = 644, giving an average of 644 ÷ 28 = 23 — matching the given condition and confirming the result.