Average weight of 15 boys in a class is 48 kgs. The average weight of the class of 25 students is 45 kgs. What is the average weight of the 15 girls in the class? Pick one.
A) 45  B) 47.3  C) 39.8  D) 45.5  E) 40.5

Rationale: total weight of boys in class 15 x 48 = 720 kg total weight of all student in the class room 25 x 45 = 1125 kg total no of girls in the class 1125 - 720 = 405 kg average weight of girls 405 / 10 = 40.5 kg correct ans is e
Answer: E