Three minutes.
If the slices are A, B and C and the sides are 1 and 2, you can do:
A1 + B1
A2 + C1
B2 + C2
Puzzle
A great delicacy in the UK is fried bread.
You fry a slice on one side, then turn it over to do the other side.
In my pan I can do one side each of two slices at one time.
To cook a side properly takes one minute.
How long does it take to do three slices of bread on both sides?