Conditional format problem

Closed
sharky9000
Posts
3
Registration date
Saturday December 6, 2014
Status
Member
Last seen
December 7, 2014
- Dec 6, 2014 at 05:03 PM
I have 3 columns Column A start time (hh:mm) Column B finish time (hh:mm) Column C is total Time (hh:mm) where C is (24-A1)+B1 etc
How can I hide the value 00:00 in column C if there are no values in columns A & B
I have tried using IFBLANK on Column A
I have tried using IFBLANK on Column B
I have tried using IFBLANK on Columns A & B
I have tried conditional formatting Column C where cells = 00:00 to be White Font
But so far nothing works any help would be appreciated as I don't like looking at 00:00 I'm lost.

A B C
1 22:00 05:00 7:00
2 00:00
3 21:58 06:15 8:17
4 00:00
5 00:00
6 00:00