Multiple choice

The ratio of the number of boys and girls in a class is 2 : 3. The average weight of boys and girls in the class is 18 kg and 21 kg respectively. What is the average weight (in kgs) of all the boys and girls together?

  1. 99/5

  2. 101/5

  3. 109/6

  4. 96/5

  5. 100/5
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A Correct answer
Explanation

Let number of boys be 2x and girls be 3x. Total weight = (2x * 18) + (3x * 21) = 36x + 63x = 99x. Total number of students = 5x. Average = 99x / 5x = 99/5.

AI explanation

Let the number of boys be 2 and the number of girls be 3. The total weight of the boys is 2 multiplied by 18, giving 36 kg. The total weight of the girls is 3 multiplied by 21, giving 63 kg. The combined weight is 99 kg for 5 total students, so the average weight is 99 divided by 5, which equals 99/5.

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