SOLUTION: Five locks and five keys of lock fall down to the ground. Then how many tries are needed match each lock with its correct key?

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Question 850091: Five locks and five keys of lock fall down to the ground. Then how many tries are needed match each lock with its correct key?
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
take key one try it in 5 locks
you find it on last try
take key 2 and try it in 4 locks and find it on last try.
5+4
take key 3 and try it on 3 locks
now two locks

one key left and it must work.
5+4+3+2=14 tries to be sure.