Multiple choice

The average weight of three persons A, B and C is 84 kg. The other person gets involved in the group is D and now the average is 80 kg. If another person, whose weight is 3 kg more than D, is replaced with A, then the average weight of B, C, D and E becomes 79 kg. How much is the weight of A?

  1. 70 kg

  2. 91 kg

  3. 75 kg

  4. 65 kg

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Average of A, B, C = 84 kg. Total (A+B+C) = 84×3 = 252 kg. Average of A, B, C, D = 80 kg. Total (A+B+C+D) = 80×4 = 320 kg. So D = 320-252 = 68 kg. E's weight = D+3 = 68+3 = 71 kg. Average of B, C, D, E = 79 kg. Total (B+C+D+E) = 79×4 = 316 kg. But D+E = 68+71 = 139 kg. So B+C = 316-139 = 177 kg. From first equation: A = 252-(B+C) = 252-177 = 75 kg. Option C is correct.

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