A boy found that the average of 20 numbers is 35 when he

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A boy found that the average of 20 numbers is 35 when he writes a number ‘61’ instead of ‘16’. The correct average of 20 numbers is

Given that , The average of 20 numbers = 35
When a boy writes a number ‘61’ instead of ‘16’ , then

Correct average = 35 +		61 -16
		20

Correct average = 35 -	45	= 35 - 2.25 = 32.75
	20

Second method to solve this question with the help of given formula :
Here, n = 20, m = 35 , a = 16, b = 61

Correct mean = m +	(a - b)
	n

Correct mean = 35 +	(16 - 61)
	20

Correct mean = 35 -	45
	20

Correct mean = 35 – 2.25 = 32.75