Question

3. The mean of 10 observation is 42. Find the sum of these 10 observations​

Answer 1

Answer:

the sum of these 10 observations​ is 30.

Step-by-step explanation:

Mean=sum of total observation /total number of observation

42=sum of total observation /10

420=sum of total observation

Now each member of the observation is decreased 12

=12*10=120

New sum of total observation =420-120

=300

New mean =300/10

=30

OR

SHORT FORMULA

NEW MEAN =MEAN - THE COMMEN NUMBER DECREASED

=40-12

=30

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Answer 2

mean = sum of observation /no of observation. so, mean (42) = sum of observation /no of observation 10. sum of observation =42 X 10 = 420