There are three piles of books A,B and C having 3,4,5 books respectively.These books have to be picked up and put in a shelf one by one.How many possible sequence can be formed in the shelf if a book can be picked only from top of any pile?
Answers: A) 12! B) 3!*4!*5! C) 12C3*9C4 D) 12^12 E) 12^14
SINCE WE SHOUL12^12 FILL ONLY FROM TOP.........12! IS NOT CORRECT   WE HAVE POSSIBILTY OF FILLING ALL 5 FROM C AN12^12 GO TO A,B 0R 1 EACH FROM EACH PILE OR 2..........SO 3!*4!*5! AN12^12 12C3*9C4 ARE ALSO WRONG.REMAINING OPTION IS ........12^12   ANSWER:12^12
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There are three piles of books A,B and C having 3,4,5 books respectively.These books have to be picked up and put in a shelf one by one.How many possible sequence can be formed in the shelf if a book can be picked only from top of any pile?