The mean weight of 150 students in a class is 60 kg. The mean weight of boys in the class is 70 kg and that of girls is 55 kg. What is the ratio of number of boys to number of girls?
- A. 1:2 ✓
- B. 1:1
- C. 2:1
- D. 2:3
Correct Answer: A. 1:2
Explanation
Using the alligation method: the ratio of boys to girls is (60 - 55) : (70 - 60) = 5 : 10 = 1 : 2.
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