The average weight of 45 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 ?
Pick
A) 51 1⁄3  B) 52 2⁄3  C) 52 1⁄3  D) 43.42  E) None of these
Total weight of 45 students   = 45 × 52 = 2340 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 45 students   = 2340 – 240 + 270 = 2370   ⇒ New average weight = 2370⁄45 = 522⁄3 kg   Answer 52 2⁄3
<result>B</result>
The average weight of 45 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 ?