there are 2 sections a and b in a class , consisting of 30 and 20 students respectively . if the average weight of section a is 40 kg and that of section b is 35 kg , find the average of the whole class ?
"total weight of 36 + 44 students = 30 * 40 + 20 * 35 = 1900 average weight of the class is = 1900 / 50 = 38 kg answer is d"
divide(add(multiply(30, 40), multiply(20, 35)), add(30, 20))