Answer:
32760 different schedules are possible.
Step-by-step explanation:
The order is important.
For example
Prague on Monday, Berlin on Tuesday, Liverpool on Wednesday and Athens on Thursday is a different schedule than Berlin on Monday, Prague on Tuesday, Liverpool on Wednesday and Athens on Thursday.
So we use the permutations formula to solve this question.
Permutations formula:
The number of possible permutations of x elements from a set of n elements is given by the following formula:
[tex]P_{(n,x)} = \frac{n!}{(n-x)!)}[/tex]
How many different schedules are possible?
Choose 4 cities among a set of 15. So
[tex]P_{(15,4)} = \frac{15!}{(15-4)!)} = 32760[/tex]
32760 different schedules are possible.
