500
Mr. Smith works on the 13th floor of a 15 floor building. The only elevator moves continuously through floors 1,2, . . . ,15,14, . . . ,2,1,2, . . ., except that it stops on a floor
on which the button has been pressed. Assume that time spent loading and unloading passengers
is very small compared to the traveling
time.Mr. Smith complains that at 5pm, when he wants to go home, the elevator almost always goes up when it stops on his floor. What is the explanation?
The elevator will almost always be going up with a 13 out of 15 chance because when he ends his work the elevator needs to be on floor 14 or 15 to go down but to go up the elevator can be on floor 1,2,3,4,5,6,7,8,9,10,11,12 or 13.