the average of 20 results is 65 and the average of other 65 results is 20 . what is the average of all the results ?
"answer sum of 85 result = sum of 20 result + sum of 65 result . = 20 x 65 + 65 x 20 = 2600 correct option : a"
divide(add(multiply(20, 65), multiply(65, 20)), add(20, 65))