The average marks secured by 36 students was 52. But it

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The average marks secured by 36 students was 52. But it was discovered that an item 64 was misread as 46. What is the correct mean of marks ?

Here ,The average marks secured by 36 students = 52
Difference of correct and incorrect marks = 64 – 46 = 18

∴ Correct mean = 52 +	18
	36

Correct mean = 52.5
Second method to solve this question with the help of given formula :
Here, n = 36, m = 52 , a = 64, b = 46

New mean = m +	(a - b)
	n

New mean = 52 +	(64 - 46)
	36

New mean = 52 +	18
	36

New mean = 52 +	1	= 52.5
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