if the average marks of 3 classes of 55 , 60 and 45 students respectively is 50 , 55 , 60 , then find the average marksof all the students is
required average = 55 x 50 + 60 x 55 + 45 x 60 55 + 60 + 45 = 2750 + 3300 + 2700 160 = 8750 160 = 54.68 c
divide(add(add(multiply(55, 50), multiply(60, 55)), multiply(45, 60)), add(60, add(55, 50)))