Average weight of 40 students in a class is 55 kg. Six of them whose average weight is 52 kg left the class and another set of six students, whose average weight is 42kg joined the class. What is the next average weight of the class (in kg?)

Average weight of 40 students in a class is 55 kg. Six of them whose a

1.	Average weight of 40 students in a class is 55 kg. Six of them whose average weight is 52 kg left the class and another set of six students, whose average weight is 42kg joined the class. What is the next average weight of the class (in kg?)
A.	54.25
B.	52.75
C.	53.5
D.	54
Answer» D. 54