In this case, we need to count up by hours and minutes.
Simple, in my opinion.
So, 11:45 to 1:12
12:45 is one hour. Now, 1:00 is another 15 minutes, so we now have 1 hour and 15 minutes.
And then, it is another 12 minutes from 1:00 to 1:12.
15 + 12 = 27
They spent 1 hour and 27 minutes at the restaurant.
Glad I could help, and good luck!
