Multiple choice

In a class of 65 students, there are 39 girls. The average weight of these girls is 60 kg and average weight of the whole class is 64 kg. What is the average weight of the boys of the class?

  1. 69 kg

  2. 66 kg

  3. 68 kg

  4. 70 kg

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

Total weight of class = 65 * 64 = 4160. Total weight of girls = 39 * 60 = 2340. Total weight of boys = 4160 - 2340 = 1820. Number of boys = 65 - 39 = 26. Average weight of boys = 1820 / 26 = 70 kg.

AI explanation

The total weight of the class is 65 students multiplied by the average of 64 kg, giving 4160 kg. The total weight of the 39 girls is 39 multiplied by 60 kg, which is 2340 kg, making the total weight of the boys 4160 minus 2340, or 1820 kg. Since there are 26 boys, dividing their total weight of 1820 kg by 26 gives an average weight of 70 kg.