Question

The mean of 5 numbers is 30. If one number is excluded, the new mean is 27. find the excluded observation. *

Answer 1

QUESTION :

The mean of 5 numbers is 30. If one number is excluded, the new mean is 27. find the excluded observation.

ANSWER :

Let a,b,c,d and e are five numbers

Average of a data = sum of total observations / total number of observations

According to the question,

Mean = 30(a +b+ c+ d+e)/5 = 30

⇒ (a +b+ c+ d+e) = 150 ..(1)

Let the number excluded be a

Then,New mean = (b+ c+ d+e)/4 = 27

⇒ (b+ c+ d+e) = 108

Substituting this in equation (1),

⇒a + 108 = 150

⇒ a = 150 – 108= 42

Therefore, excluded number = 42

FINAL ANSWER : 42