5 seconds
2 seconds
5 seconds
15 seconds
25 seconds
3 seconds
42 seconds
2 seconds
5 seconds
11 seconds
30 seconds
14 seconds
21 seconds
104 seconds
15 seconds
3 seconds
17 seconds
11 seconds

My Column is as above I want to add all these seconds and come up with an average.
But I cannot add them up because of the word seconds.

How can I either add all these seconds with the word, or extract the word seconds from the entire column, or extract the number of seconds to another column ?
HELP????