# The mean of the marks scored by 50 students was found to be 39.

Question:

The mean of the marks scored by 50 students was found to be 39. Latter on it was discovered that a core of 43 was misread as 23. The correct mean is
(a) 38.6
(b) 39.4
(c) 39.8
(d) 39.2

Solution:

(b) 39.4

Mean of the marks scored by 50 students = 39

Sum of the marks scored by 50 students $=(39 \times 50)=1950$

Correct sum $=(1950+43-23)=1970$

$\therefore$ Mean $=\frac{1970}{50}=39.4$