Hello:

I have data that looks like the following:
3:09:15
22:45:07
17:39:10
17:39:10
18:52:47
8:39:35

I would like to learn a formula that will round the time to the top and
bottom of the hour using the 15 and 45 as the break point. For example
3:09:15 to 3:00. 17:39:10 to 17:30.

Thanks for the hedlp.
Jim