Rohit found the mean of 20 numbers to be 32. He then noticed that he had copied one number as 72 instead of 27, and had also missed out a 21st number. After both corrections the mean of the 21 numbers is 30. What is the missed number?
Competition practiceStatistics
A35
B33
C30
D45
Step-by-Step Solution
Corrected sum of 20 =640−72+27=595. Sum of 21 =21×30=630. Missed number =630−595=35.
Answer: A) 35
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