Three wolves and four sheep are put in a separate cage, respectively.
I would like to move these seven animals one by one into one cage.
Sheep will be eaten by wolf if the number of wolf is more than the number of sheep.
If it is the same number, sheep can not be eaten.
How many ways of movement for a sheep not to be eaten are there?
Answer
19 ways
Solution
Moving one wolf to the cage is assumed to be moving upward by one block.
Moving one sheep is assumed to be moving rightward by one.
Then it can be considered as shown in a figure below.
Therefore, there are 19 ways at all.
× mark means that it cannot be moved.
I would like to move these seven animals one by one into one cage.
Sheep will be eaten by wolf if the number of wolf is more than the number of sheep.
If it is the same number, sheep can not be eaten.
How many ways of movement for a sheep not to be eaten are there?
Answer
19 ways
Solution
Moving one wolf to the cage is assumed to be moving upward by one block.
Moving one sheep is assumed to be moving rightward by one.
Then it can be considered as shown in a figure below.
Therefore, there are 19 ways at all.
× mark means that it cannot be moved.
