A room has 5 doors. In how many ways can a man enter the room through one and come out through a different door?
Asked by Topperlearning User | 4th Jun, 2014, 01:23: PM
The man has to perform two jobs in succession:
1) He has to enter the room, then
2) He has to come out from the room
Clearly, a person can enter the room through anyone of the 5 doors, So he can perform first job in 5 ways. After entering into the room, the man can come out through a different door in 4 ways.
Hence the number of ways in which a man can enter a room through one door and come out through a different door = 5 x 4 = 20
Answered by | 4th Jun, 2014, 03:23: PM
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