Solve this Puzzle

A man wanted to enter an exclusive club but did not know the password
that was required. He waited by the door and listened.

A club member knocked on the door and the doorman said, "twelve." The
member replied, "six " and was let in.

A second member came to the door and the doorman said, "six." The
member replied, "three" and was let in.

The man thought he had heard enough and walked up to the door. The
doorman said ,"ten" and the man replied, "five."

But he was not let in. What should have he said?

Comon guys, put on your thinking caps & get the solution......



Please put ur answer in the Comments and i ll let u know whether ur right or not through my reply.