Calculation help

[spray2006]

Hi guys,
Your help will be very much appreciated -
So here is my problem. I have a column that has 5 average values of 10
10
10
10
10
10
Now if I change the 3rd value (or 3rd row) to say 15 how do I make sure
that the average for the column remains the same (i.e. 10) but the
values in last 2 rows changes --> i.e it should be 7.5 and 7.5.
The values in the first two rows should not change and the cloumn
should appear as
10
10
15
7.5
7.5
Any help will be appreciated.

Thanks
spray2006

 

[paul]

will it always be the third row to change and 4 and 5 to correct????

 

[spray2006]

Hi Paul,
Thanks for the reply.
No...it can be any row. the challenge is i have to change the values of
the rows below the one that I change so that the average remains
constant.

spray2006