the mean of 30 values was 250 . it was detected on rechecking that one value 165 was wrongly copied as 135 for the computation of the mean . find the correct mean .
"corrected mean = 250 × 30 − 135 + 165 / 30 = 7500 − 135 + 165 / 30 = 7530 / 30 = 251 answer d"
divide(add(multiply(30, 250), subtract(165, 135)), 30)