probability hard problems
5 keys are randomly placed among 3 places designated as p1,p2 and p3 Find the probability of the following events
1- place p1 is empty
2- place p1 and only p1 is empty
3- exactly 1 place is empty
4- At least 1 place is empty
5- No place is empty
6- 2 places are empty
7- 3 places are empty
8- either p1 or p2 is empty
Repeat the above experiment with n keys and three places Check you general expression against your answer to above experiment
The persons p1 p2 p3 are among those 10 persons who have placed their cheques on a counter.Each person take a cheque random from the cheques on the counter. What is the probability that at least one either p1 p2 or p3 will get his own cheque?