The mean weight of 100 students in a class is 46 kg. The mean weight of boys is 50 and of girls is 40 kg. Therefore, the number of boys is _____?
- 40
- 50
- 60
- None of these
Explanation
Let number of boys are x and then number of girls
= (100 - x)
Thus,
50x + (100 - x) × 40 = 46 × 100
→ x = 60
Number of boys = 60
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