I have an excel spreadsheet that has time entered in for minutes and
seconds; ie 7 minutes and 28 seconds is shown as 7.28. How do I sum a
column with increments of time.

example:
7.28 (7 minutes & 28 seconds)
2.38 (2 minutes & 38 seconds)
5.48 (5 minutes & 48 seconds)

Total time should result in 15.54 (15 minutes & 54 seconds), but if I do a
simple SUM, the results are 15.14. HELP!