The mean of six numbers is 23 If one of the numbers is
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The mean of six numbers is 23. If one of the numbers is excluded, the mean of the remaining numbers is 20. Find the excluded number.
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Right Answer is:
SOLUTION
ANSWER:
Let the numbers be x 1 , x 2 ,..., x 6 .
Mean = 23
We know:
Mean =Sum of observations / Number of observations
Thus, we have:
23 = x1+x2+...+x6/6
x1+x2.......x6=138.....................(i)
If one number, say, x 6 , is excluded, then we have:20 = x1+x2+...+x5/5
x1+x2......+x5=100....................(ii)
Using (i) and (ii), we get:
138 = x1+x2+...+x5+x6⇒138 = 100+x6
...(i)⇒ x6=38
Thus, the excluded number is 38