Multiple choice

If the average weight of the whole class is 50 kg. And the average weight of boys in the class is 60 kg and the average weight of girls in the same class is 44 kg. What could be the possible ratio of strength of boys and girls in the class respectively?

  1. 2: 3

  2. 3: 4

  3. 4: 5

  4. 3: 5

  5. 1: 2
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Using weighted average formula: Average = (b×60 + g×44)/(b+g) = 50. So 60b + 44g = 50(b+g), 60b + 44g = 50b + 50g, 10b = 6g, b:g = 6:10 = 3:5. Option D (3:5) satisfies: (3×60 + 5×44)/(3+5) = (180 + 220)/8 = 400/8 = 50. Option A gives 52, B gives 51.43, C gives 50.89, E gives 52 - none equal 50.

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