If lunch break is in decimal, formula is what I supplied
E2: = 24 * (D2 - B2 + (B2D2)) - C2 format as decimal number 0.00
no problem with entering decimal time for break period, if in increments of .25 (15 minutes)

If lunch break is as h:mm, formula would be
E2: = 24 * (D2 - B2 + (B2D2) - C2 ) format as decimal number 0.00