The average of marks in Mathematics for 5 students was found

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The average of marks in Mathematics for 5 students was found to be 50. Later, it was discovered that in the case of one student the marks 48 were misread as 84. The correct average is :

1. 40.2
2. 40.8
3. 42.8
4. 48.2

Correct Option: C

Here , The average of marks in Mathematics for 5 students was found to be 50
Total marks obtained by 5 students = 50 × 5 = 250.
Now, in this total marks, 84 is included instead of 48.
∴ Correct total marks = 250 – 84 + 48 = 214
∴ Correct average = 214 ÷ 5 = 42.8
Second method to solve this question with the help of given formula :
Here, n = 5, m = 50 , a = 48 , b = 84

Correct Average = m +	(a - b)
	n

Correct Average = 50 +	(48 - 84)
	5

Correct Average = 50 -	36
	5

Correct Average = 50 – 7.2 = 42.8