This is problem 4 from section 2.3 of(adsbygoogle = window.adsbygoogle || []).push({}); Fundamentals of Probabilityby Saeed Ghahramani.

1. The problem statement, all variables and given/known data

Robert has eight guests, two of whom are Jim and John. If the guests will arrive in a random order, what is the probability that John will not arrive right after Jim?

2. Relevant equations

...

3. The attempt at a solution

There are 8! ways for the guests to arrive. There are 7 ways for John to arrive right after Jim. The probability of John arriving right after Jim is then 7/8!, and the probability of John not arriving right after Jim is 1-7/8!=0.9998.

I am pretty sure it is right, but not 99.98% sure.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Permutation homework

**Physics Forums | Science Articles, Homework Help, Discussion**