3 types of bread, 2 types of cheese, and 3 types of meat.
I have attempted a tree diagram below:
A—> american cheese
S—>Swiss cheese
T—>turkey
P—>pastrami
H—>ham
white bread french bread rye bread
| | |——————- —————- -—————
| | | | | | | | |
T H. P. T. H. P. T. H. P
| | | | | |. | | |
—- —- —- —- —- —- —- —- —-
| | | | | | | | | | | | | | | | | |
A S A. S. A. S A. S. A. S A. S. A. S. A. S A S
Therefore you can know the number of combinations by counting the branches at the bottom so there are 18 combinations total. I hope this helps