There are 2 sections A and B in a class, consisting of 40 and 30 students respectively. If the average weight of section A is 50kg and that of section B is 60kg, Find the average of the whole class?  Choose the correct answer:	A) 50.78 kg	B) 49.32 kg	C) 61.67 kg	D) 69.15 kg	E) 54.28 kg

Rationale: "total weight of 40 + 30 students = 40 * 50 + 30 * 60 = 2000 + 1800 average weight of the class is = 3800 / 70 = 54.28 kg answer is e"
Answer: E