a school has 4 section of chemistry in class x having 65 , 35 , 45 and 42 students . the mean marks obtained in chemistry test are 50 , 60 , 55 and 45 respectively for the 4 sections . determine the overall average of marks per student .
required average marks = 65 ã — 50 + 35 ã — 60 + 45 ã — 55 + 42 ã — 45 / 65 + 35 + 45 + 42 = 3250 + 2100 + 2475 + 1890 / 187 = 9715 â  „ 187 = 51.95 answer c
divide(add(add(add(multiply(65, 50), multiply(35, 60)), multiply(45, 55)), multiply(42, 45)), add(add(add(65, 35), 45), 42))