In how many ways can the first 4 guests arrive at a party if 15 guests have been invited.

The first 4 guests can arrive in 32,760 ways.

Step-by-step explanation:

The order in which the guests arrive is important. For example, A,B,C,D is a different outcome to B,A,C,D. 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:

In this question:

4 guests from a set of 15. So

The first 4 guests can arrive in 32,760 ways.