The average weight of 49 students in a class is 52 kg. 5 of them whose average weight is 48 kg leave the class and other 5 students whose average weight is 54 kg join the class. What is the new average weight (in kg) of the class ?	Choices:  A) 51 1⁄3  B) 52 30/49  C) 52 1⁄49  D) 43.42  E) None of these
Total weight of 49 students   = 49 × 52 = 2548 kg   Total weight of 5 students who leave   = 5 × 48 = 240 kg   Total weight of 5 students who join   = 5 × 54 = 270 kg   Therefore, new total weight of 49 students   = 2548 – 240 + 270 = 2578   ⇒ New average weight = 2578⁄49 = 52 30/49 kg   Answer 52 30/49
<result>B</result>
The average weight of 49 students in a class is 52 kg. 5 of them whose average weight is 48 kg leave the class and other 5 students whose average weight is 54 kg join the class. What is the new average weight (in kg) of the class ?