The mean marks of 30 students in a class is 58.5. Later on it was found that 75 was wrongly recorded as 57. Find the correct them.
A. 57.4
B. 57.5
C. 58.9
D. 59.1
Correct mean = 30x 58.5 -57 +75/30
= 1755+18/30 = 1773/30 = 59.1