The average weight of 60 students in a class is 56.4 kg. If 12 students having average weight 59.5 kg leave the class and 15 students having average weight 54 kg join the class, then what is the average weight (in kg) of the students in the class (correct to one decimal place)?
Answer & explanation
Correct answer: option 2
Sum of weight of 60 students = 60 × 56.4 = 3384 kg
12 students leave the class , Sum of weight of 12 students = 12 × 59.5 = 714 kg
15 students join the class , Sum of weight of 15 students = 15 × 54 = 810 kg
Increment in weight = 810 - 714 = 96 kg
New average of 64 students = \(\frac{3384 + 96}{63}\) = \(\frac{3480}{63}\)
= 55.2 kg