the average of 40 results is 30 and the average of other 30 results is 40 . what is the average of all the results ?
answer sum of 70 result = sum of 40 result + sum of 30 result . = 40 x 30 + 30 x 40 = 2400 / 70 correct option : a
divide(add(multiply(40, 30), multiply(30, 40)), add(40, 30))