Civil Services Prep

Prelims 2022 · CSAT / Quantitative Aptitude · Question 80

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?

  1. 40.5 kg
  2. 40.8 kg
  3. 41 kg
  4. Cannot be determined as data is inadequate

Answer

41 kg

Re-examination: My earlier conclusion was incorrect.

  • A + B + C = 3 × 40 = 120.
  • B + D + E = 3 × 42 = 126.
  • Given F = B, total of six = A + B + C + D + E + F = (A+B+C) + (B+D+E) = 120 + 126 = 246.

So average of A, B, C, D, E, F = 246/6 = 41 kg.

Option check:

  • (a) 40.5 kg — Incorrect; total would have to be 243.
  • (b) 40.8 kg — Incorrect; total would have to be 244.8.
  • (c) 41 kg — Correct; total is 246, average is 41.
  • (d) Cannot be determined — Incorrect; data is sufficient.
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