Answer:
0.143
Step-by-step explanation:
From counting principle, we can say that:
There are 7! ways of the 7 people to arrive first. Any one of them can come first. But, what is the probability that Xerxes with arrive first?
We take that Xerxes is the first one to arrive, then from the 7 - 1 = 6 remaining people, they can arrive in 6! ways. So
Probability Xerxes arrives first = 6!/7! = 0.1429
Rounding to 3 decimal places, it will be:
Probability Xerxes arrives first = 0.143