Answer:
The answer is 48
Explanation:
For every different sandwich, she needs to choose one breat, one meat and one cheese.
For each choice of bread, there are 4 choices of meat and 4 choices of cheese. Also, for each meat, there are four choices of cheese. It means that for each bread there are 4(choices of meat)*4(choices of cheeses) = 16 possible combinations.
There are also 3 choices of breads. For each bread, there are 16 possible combinations. So, in all, there are 3*16 = 48 possible combinations.