Mathematics
Mean of 20 observations (numbers) is 30. If one number is excluded, the mean of remaining numbers becomes 28. The excluded number is :
532
1132
68
572
Statistics
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Answer
Given:
Mean of 20 observations = 30
⇒ Sum of all 20 observations = 30 x 20 = 600
On excluding an observation, the mean of the remaining 19 observations = 28
∵ Sum of all remaining 19 observations = 28 x 19 = 532
⇒ Excluded observation = Sum of all 20 observations - Sum of all remaining 19 observations
= 600 - 532
= 68
Hence, option 3 is the correct option.
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