I've created a simple worksheet to return the difference between two times,
however, the first time is being reported incorrectly by 2 hours.

B2 - 11:00
C2 - 18:30
D2 - =C2-B2

MS Excel 2007

The result of D2 is returned as 07:30, whilst this should read 05:30. This
problem does not happen with another cell.
Am I using some incorrect formula?