Multiple choice

The average weight of 52 boys in a class was estimated to be 38 kg, whereas the total weight of 48 girls in the same class was estimated to be 1728 kg. If with the addition of 10 new students to the class, the average weight for the class changed to 38 kg, what was the average weight of the 10 new students?

  1. 47.6 kg

  2. 48.6 kg

  3. 49.6 kg

  4. 50.6 kg

  5. 51.6 kg

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Total weight of 52 boys = 52 * 38 = 1976. Total weight of 48 girls = 1728. Total weight of 100 students = 1976 + 1728 = 3704. New total students = 110. New average = 38. New total weight = 110 * 38 = 4180. Weight of 10 new students = 4180 - 3704 = 476. Average = 476 / 10 = 47.6 kg.