a school has 4 section of chemistry in class x having 55 , 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 = 55 ã — 50 + 35 ã — 60 + 45 ã — 55 + 42 ã — 45 / 55 + 35 + 45 + 42 = 2750 + 2100 + 2475 + 1890 / 162 = 9215 â  „ 177 = 52.06 answer b"
divide(add(add(add(multiply(55, 50), multiply(35, 60)), multiply(45, 55)), multiply(42, 45)), add(add(add(55, 35), 45), 42))