Answer:
The number of path we can take to walk from A to B via a 7 unit path while staying on the grid is 35 paths
Step-by-step explanation:
Given that we are to walk via a 7 unit path, we have;
Path to walk = Right or Left from start point A
Total number of rights and left to get to point B from A must be 7
3 of the turns have to be in the left direction while 4 of the turns are right
Therefore, in 7 turns we have 4 in the right direction and 3 in the left direction which gives;
Number of ways for the first turn = 7, the next turn has 6 ways after that 5 and so on so we have;
7 × 6 × 5 × 4 × 3 × 2 × 1 out of which four are in the right direction in 4 × 3 × 2 × 1 ways and 3 are in the left direction in 3 × 2 × 1 ways, which gives the number of ways as follows;
[tex]Number \, of \, ways = \dfrac{7\times 6\times 5\times 4\times 3\times 2\times 1}{4\times 3\times 2\times 1 \times 3\times 2\times 1 } =\dfrac{5040}{144} = 35[/tex]
Therefore, there are 35 paths we can take to walk from A to B via a 7 unit path while staying on the grid.
