Question

the mean of 5 observations is 40. the mean of 4 of them is 38. find the 5th observation.

Answer 1

$mean = \frac{sum \: of \: observations}{number \: of \: observations} \\ 40 = \frac{x}{5} \\ x = 200$
Where x is sum of 5 observations

Now,
$38 = \frac{y}{4}$
where y is sum of 4 observations,
Therefore, y=38×4=152
x-y = 5th observation
5th observation is 200-152=48


HOPE IT HELPS

Answer 2

Answer:

The 5th observation is 48.

Step-by-step explanation:

Given the mean of 5 observations is 40. the mean of 4 of them is 38. we have to find the 5th observation.

$mean =\frac{\text{sum of observations}}{\text{number of observations}}$

$40=\frac{x}{5}$

$x = 200$

Where x is sum of 5 observations

Now,  $38 = \frac{y}{4}$  

where y is sum of 4 observations,

Therefore, y=38×4=152

5th observation=x-y

5th observation is 200-152=48

hence, the 5th observation is 48.