the mean of 30 values was 180 . it was detected on rechecking that one value 155 was wrongly copied as 135 for the computation of the mean . find the correct mean .
"corrected mean = 180 × 30 − 135 + 155 / 30 = 5400 − 135 + 155 / 30 = 5420 / 30 = 180.67 answer e"
divide(add(multiply(30, 180), subtract(155, 135)), 30)