Need help correcting this formula please. using excel 2003.

Col B is start time
Col C is end time
Col D =(C2-B2)*24
Col E =IF(D2<=5,D2,IF(D25<10,(D2-0.5),IF(D2=10,(D2-1.0))))

Works of when the time is less than 5 hours and more than 10 hours, but when
the time is more than 5 and less than 10 the answer is "False"

Please help me fix this error.

Thanks in advance

chefmike