The average weight of A, B, C is 40 kg, the average weight of B, D, E is 42 kg and the weight of F is equal to that of B. What is the average weight of A, B, C, D, E and F?
Answer & explanation
Answer: (c) 41 kg
A + B + C = 120 and B + D + E = 126. Since F weighs the same as B, the six weights total 120 + 126 = 246 kg, and the average is 41 kg even though B itself is unknown.
- A + B + C = 3 × 40 = 120 kg and B + D + E = 3 × 42 = 126 kg.
- Since F = B, A + B + C + D + E + F = (A + B + C) + (F + D + E) = 120 + (B + D + E) = 120 + 126 = 246 kg.
- Average = 246 ÷ 6 = 41 kg.
Remember · Before answering ‘cannot be determined’, check whether the unknown cancels — here F = B fills the gap exactly.
Question and answer: UPSC's official GS Paper II (2022, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·