Maths WorkshopMaths problems with full solutions
Exercise 890Combinatorics › Counting principlesOlympiadAdded 3 Nov 2026

Monotone lattice paths

#lattice paths#binomial#counting

Statement

How many shortest paths from (0,0)(0,0) to (5,3)(5,3) on a grid (only right/up moves)?

Hint

Choose positions of 55 right moves among 88 total.

Show solutionHide solution

Solution

Paths. (85)=56\binom{8}{5}=56.

Conclusion. 5656 shortest paths.