Multiple choice

There are 50 students in a class. One of them weighing 50 kg goes away and a new student joins. By this the average weight of the class increases by (\frac{1}{2}) kg. The weight of the new student is

  1. 70 kg

  2. 72 kg

  3. 75 kg

  4. 76 kg
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let original average be A. Original total = 50A. New total = 50A - 50 + W (where W is new student's weight). New average = A + 0.5. So (50A - 50 + W)/50 = A + 0.5. Solving: 50A - 50 + W = 50A + 25, so W = 75 kg.

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