Averages · Question 25 · Medium
Averages question 25
In a class, the average weight of 30 boys is 50 kg and the average weight of the girls is 45 kg. If the average weight of the whole class is 48 kg, how many girls are there?
- 18
- 25
- 45
- 20
Answer and explanation
Answer: D. 20
Explanation: 30 × 50 + 45g = 48(30 + g) gives 1500 + 45g = 1440 + 48g, so 3g = 60 and g = 20.
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