Multiple choice

There are 50 boys in a class. One boy weighing 40 kg goes away and at the same time another boys joins the class . if the average weight of the class is thus decreased by 100 g find the weight of the new boy ?

  1. 32 kg

  2. 40 kg

  3. 35 kg

  4. 37 kg
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total weight change = 50 * 0.1 kg = 5 kg decrease. New weight = Old weight - 5 kg = 40 - 5 = 35 kg.

AI explanation

Using the method of average change, the total decrease in weight for the class of 50 boys is 50 times 100 g, which equals 5000 g or 5 kg. Because the 40 kg boy left and was replaced by the new boy, this means the new boy weighs 5 kg less than the boy who left. The weight of the new boy is therefore 40 - 5 = 35 kg. The result is 35 kg.

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