The mean of 50 observations was 36. It was found later that an observation 45 was wrongly taken as 23. The corrected new mean is?  Options.
A) 36.7
B) 36.4
C) 36.5
D) 36.9
E) 36.3

Rationale: "correct sum = ( 36 * 50 + 45 - 23 ) = 1822 . correct mean = 1822 / 50 = 36.4 answer : b"
Answer: B