Excel Round Up time to the nearest minute from total of 2 cells

I have a worksheet that is filled in from a userform and have the date + time filled in to 2 different cells, basically from a start and stop button. The button fills current date and time in the cells. So I have it set like this:

Cell A1 Start = "04/15/2012 4:15:27"
Cell A2 Stop = "04/15/2012 5:38:42"
Cell A3 = A2-A1

My Cell C3 Formula: =(+A2-A1)*24

I need to have my formula calculate an even time..... like 1.4 / 1.5 / 1.6 hours etc. But instead when I call this number back to the userform I get this: 1.38749999989523
I only want it to round up to the nearest tenth of an hour.

How can I make cell A3 show a rounded UP time to the nearest minute no matter what the second is? I have found some examples but nothing for what I need. I already have the Cell A3 formula set for subtracting the time, so not sure how to add this or what to change.

Thanks for your help, I am really stuck on this.

Thank You SO very much daddylonglegs for the help.... this works like a charm. Much appreciated!!

Thanks shg... this works very well. Very much appreciated.