the mean of five numbers is 30. if one number is excluded, their mean becomes 28. the excluded number is:
Answers
mean = (a +b+ c+ d+e)/5 = 30
⇒ (a +b+ c+ d+e) = 150_______(1)
now, Let the number excluded be a
then, new mean = (b+ c+ d+e)/4 = 28
⇒ (b+ c+ d+e)= 112
putting this value in (1),
⇒a + 112 = 150
⇒a = 150 -112 = 38
∴ excluded number = 38
Given :- The mean of five numbers is 30. If one number is excluded, their mean becomes 28. What is the excluded number ?
Solution :-
we know that,
- Mean = (sum of observations)/(Total number of observations)
so,
→ Mean = (sum of observations)/5
→ 30 * 5 = sum of observations
→ sum of observations = 150 .
now, given that, 1 number is excluded .
then,
→ Total numbers = 5 - 1 = 4
→ Mean = 28
therefore,
→ sum of observations = Mean * Total numbers = 28 * 4 = 112 .
hence,
→ Excluded Number = sum of 5 numbers - sum of 4 numbers = 150 - 112 = 38 (Ans.)
∴ The Excluded Number is 38.
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