Mathbound
Sign up

Daily puzzle · 2026-11-05 · Combinations

Mathbound Daily Puzzle — 2026-11-05 — Combinations Solution

Level 3

Lattice paths (0,0)→(8,8)(0,0)\to(8,8) with steps (1,0),(0,1)(1,0),(0,1) avoiding (4,2)(4,2). How many?
  1. A.9720
  2. B.9710
  3. C.12870
  4. D.3150
  5. E.9790

Answer: A

Key idea: (2nn)\binom{2n}{n} minus paths through the obstacle.

Set it up: Subtract product of binomials.

Solution: 97209720.

Browse more archived puzzles · Try today's puzzle

Mathbound Daily Puzzle — 2026-11-05 — Combinations Solution