The average weight of 49 students in a class is 39 kg. Seven of them whose average weight is 40 kg leave the class and other seven students whose average weight is 54 kg join the class. What is the new average weight (in kg) of the class?

41

Total Weight Increased will be = 7 x (54 - 40)= 7 x 14

Change in avg. = \(\frac{7 × 14}{49}\)

                      = 2

New Avg will be 39 + 2 = 41