The average of 6 observations is 45.5. If one new observation

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The average of 6 observations is 45.5. If one new observation is added to the previous observations, then the new average becomes 47. The new observation is

1. 58
2. 56
3. 50
4. 46

Correct Option: B

Let the new observation be y.
The average of 6 observations = 45.5.

Then,	y + 6 × 45.5	= 47
	7

⇒ y + 273 = 47 × 7 = 329
⇒ y = 329 – 273 = 56
Second method to solve this question with the help of given formula :
Here, y = (47 – 45.5) = 1.5 , n = 6
New observation = Average + y (n + 1)
New observation = 45.5 + 1.5 (6 + 1)
New observation = 45.5 + 10.5 = 56