If the mean of the following data is 15, find $p$.

$x$:	5	10	15	20	25
$f$:	6	$p$	6	10	5.

Given:

The mean of the given data is 15.

To do:

We have to find the value of $p$.

Solution:

  We know that, 

Mean$=\frac{\sum fx}{\sum f}$

Therefore,

Mean $15=\frac{445+10p}{27+p}$

$15(27+p)=445+10p$

$405+15p=445+10p$

$15p-10p=445-405$

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

$p=8$