Question 745070
There are 4 hotels in a certain city. If 3 men check into hotels in a day,
the probability that each check into (i) a different hotel 
the 1st man enters into a hotel 1n 4 ways
the 2nd man enters into a hotel 1n 3 ways (as one hotel is booked )
the 3rd man enters into a hotel 1n 2 ways (as two hotel is booked )
so the probability =4*3*2=24 
the probability that each check into (ii) the same hotel.
the 1st man enters into a hotel 1n 4 ways
the 2nd man enters into a hotel 1n 4 ways (as hotel is repeated )
the 3rd man enters into a hotel 1n 4 ways (as hotel is repeated)
so the probability =4*4*4=64