Multiple choice

In a class of 178 students there are 68 girls. The average weight of these girls is 51 kg and the average weight of the whole class is 55.2 kg. What is the average weight of the boys of the class?

  1. $57.8$
  2. $56.2$
  3. $59.5$
  4. $60$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Total class weight = 178 × 55.2 = 9825.6 kg. Girls' total weight = 68 × 51 = 3468 kg. Boys' weight = 9825.6 - 3468 = 6357.6 kg. Number of boys = 178 - 68 = 110. Average boys' weight = 6357.6 / 110 = 57.8 kg. Option A is correct.

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