- #1

Somefantastik

- 230

- 0

[solution]

Pn,m = P(A gets n votes, B gets m votes | last vote to A)*(n/n+m) + P(A gets n votes, B gets m votes | last vote to B) * (m/m+n)

= Pn-1,m * (n/n+m) + Pn,m-1*(m/m+n)

From the formula, we have

Pn,1 = Pn-1,1 *(n/n+1) + Pn,0*(1/n+1) = (n/n+1)*Pn-1,1 + 1/(n+1)

P1,1 = 0

=> Pn,1 = (n-1)/(n+1)

and

Pn,2 = Pn-1,2*(n/n+2) + Pn,1*(2/2+n) = Pn-1,2*(n/n+2) + 2*(n-1)/(n+2)

P2,2 = 0

==> Pn,2 = (n-2)/(n+2)

Please explain this solution to me. The stuff in red is where I got lost.