Question 31453
An elevator containing 5 people can stop at any one of 7 floors. What is the probability that no 2 people get off on the same floor? (Assume each floor is equally like for each person)
LET US DEVELOP ALOGIC LIKE THIS
THE FIRST PERSON CAN GET DOWN AT ANY ONE OF THE 7 FLOORS..IN....7 WAYS.
THE SECOND PERSON CAN GET DOWN AT ANY FLOOR OTHER THAN THE ABOVE THAT IS IN 6 WAYS 
LIKE THAT IF WE CONTINUE WE GET THE ANSWER AS 
7*6*5*4*3=2520 WAYS