Multiple choice

The average weight of a class of 15 boys and 10 girls is 38.4kg, if the average weight of the boys is 40 kg, then what is the average weight of the girls

  1. 36.5 kg

  2. 35 kg

  3. 36 kg

  4. 35.6 kg

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total weight = 25 * 38.4 = 960. Boys' total weight = 15 * 40 = 600. Girls' total weight = 960 - 600 = 360. Girls' average = 360 / 10 = 36 kg.

AI explanation

The total weight of all 25 students is 25 multiplied by 38.4, giving 960 kg, while the total weight of the 15 boys is 15 multiplied by 40, giving 600 kg. The total weight of the 10 girls is found by subtracting the boys' weight from the class total, so 960 minus 600 equals 360 kg. Using the basic average formula, the average weight of the girls is 360 divided by 10, which equals 36 kg.