Adding Two Formulas to One Cell

I need two formulas in one single cell, both doing different things, but they also rely on each other. Basically, one calculates a start time and end time, giving the hours worked. Then the second part has to subtract .50 if the hours worked are greater than 8 total hrs.

I've tried using 'AND, IF, &' and also things I've found online, but nothing seems to work.

IF(C6 < D6, 0, 1)+D6 - C6 *-24 AND IF (C6 > 8, C6 - 0.5,0)  

I've tried many different variants of this formula to no avail. Maybe I just can't combine them or maybe it isn't even possible, any help would be great!