math
posted by george .
Andrew worked from 9:45 am to 3:40 pm on Saturday.how long did he work on Saturday?
A)5 hours 50 minutes
B)5 hours 55 minutes
C)6 hours 5 minutes
D)6 hours 55 minutes
i got 6 hours 35 minutes what did i do wrong

I like changing to a 24 hour clock (adding 12 to all PM hours)
from 0945 to 1540?
subtract
1540
0945
5:55