Multiple choice

The average weight of A, B and C is 60 kg. If the average weight of A and B be 60 kg and that of B and C be 64.5 kg, then the weight of B is:

  1. 78

  2. 69

  3. 71

  4. 74
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Average of A,B,C is 60 kg, so A+B+C = 180. Average of A,B is 60 kg, so A+B = 120. Average of B,C is 64.5 kg, so B+C = 129. From A+B+C=180 and A+B=120, we get C=60. From B+C=129, B = 129-60 = 69 kg.

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