Let {Xn} be the (standard) symmetric random walk, i.e., X₀ = 0,
Xn =
n
Σn Zᵢ
n
where Z₁ , Z₂ , . . . are IID with P{Zᵢ = −1} = P{Zᵢ = 1} = 1/2.
Find P(X₁0=10)