Question 1201865
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The figure is described as a 7x22 grid of unit squares, so we don't need to see the figure....<br>
Assuming this is a problem where A and B are opposite corners of the grid, the number of paths of length 29 from A to B is<br>
{{{29!/((22!)(7!))}}}<br>
To understand the reason for that answer, let B be 22 units to the right of A and 7 units above A.  Then any path from A to B of length 29 has to move 22 "steps" to the right ("R") and 7 steps up ("U").<br>
So each path of length 29 from A to B consists of some arrangement of the symbols<br>
RRRRRRRRRRRRRRRRRRRRRRUUUUUUU<br>
By a well-known counting principle, the number of ways to do that is the number shown above.<br>
ANSWER: {{{29!/((22!)(7!))}}}<br>