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The mean of 25 observation is 36. Out of...

The mean of `25` observation is `36.` Out of these observations, if the mean of first `13` observations is `32` and that of the last `13` observations is `40,` the `13th ` observation is

A

`23`

B

`36`

C

`38`

D

`40`

Text Solution

Verified by Experts

The correct Answer is:
B
Given, mean of 25 observations = 36
`therefore` Sum of 25 observations `=36 xx 25=900`
Now, the mean of first 13 observations`=13 xx 32=416`
and the mean of last 13 observations =40
`therefore` sum of last 13 observations = (Sum of last 13 observations + Sum of first 13 observations)-(Sum of 25 observations)
`=(520-416)-900=936-900=36`
Hence, the 13th observation is `36`.
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