Mean of 10 numbers is 30. Later on it was observed that

Home » Aptitude » Average » Question

Mean of 10 numbers is 30. Later on it was observed that numbers 15, 23 are wrongly taken as 51, 32. The correct mean is

Later on it was observed that numbers 15, 23 are wrongly taken as 51, 32 .
∴ Difference = 15 + 23 – 51 – 32 = –45

∴ Correct average = 30 -	45	= 25.5
	10

Second method to solve this question with the help of given formula :
Here, n = 10, m = 30 , a = 15, b = 23 , p = 51 , q = 32

Correct Average = m +	(a + b - p - q)
	n

Correct Average = 30 +	(15 + 23 - 51 - 32)
	10

Correct Average = 30 +		38 - 83
		10

Correct Average = 30 -	45	= 25.5
	10

Correct Average = 30 – 4.5 = 25.5