There are 2 sections A and B in a class, consisting of 40 and 20 students respectively. If the average weight of section A is 50kg and that of section B is 40kg, Find the average of the whole class?  Choose one
A) 50.78 kg	B) 49.32 kg	C) 46.66 kg	D) 69.15 kg	E) 70.89 kg

Rationale: "total weight of 40 + 20 students = 40 * 50 + 20 * 40 = 2000 + 800 average weight of the class is = 2800 / 60 = 46.66 kg answer is c"
Answer: C