Thanks for reading this post...
I have some data from a hospital that I need to analyze.
Column A contains the time a surgery started
Column B contains the time the surgery ended.

A B
8:24 9:35
8:32 9:50
8:45 10:31
etc. etc.

Now, I want to be able to determine how many surgeries
were in progress at:
8:00
8:30
9:00
9:30
10:00
etc.

Any help would be greatly appreciated.
THANK YOU!
Jim