adding colums to text

I have a row of values like such, placed in a text file by fprintf.

10.50
10.25
10.00
10.75
11.00

What I want to do to the above colum is add a new column right beside it
which is a total of these values and then average them in another column.
For example.

11.00 52.50

In another column is the average of the 5.

11.00 52.50 10.50

I am assuming that fprintf is going to have to be used and maybe freopen.

Bill


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