A frog sitting on the second of three stones jumps to left with probability $0.4$, what is the probability that it will reach the zeroth stone first? > A blind frog sits on the second of three stones in a line. At each minute, it jumps either to left (with probability $0.4$) or right. To the right of third stone there is a lake in which an alligator is waiting for the frog. To the left of the first stone there is a stork waiting for the frog. Find the probability that the stork eats the frog. I tried to solve this by recurrence relations, but couldn't establish a proper definition of $a_n$. I mean $n$ can denote the stone number that the frogs is sitting, but then I have find $a_0$, and I don't know whether that kind of configurations are allowed. In another case, I can choose the second stone as my $n=0$, and $n$ can denote, again, the stone numbers, but then I need to include the negative $n$s, which, again, I don't know whether it is eligible, so I'm stuck.

**Hint:** Consider the sequence $1, p_1, p_2, p_3, 0$ such that each $p_k$ is a weighted average of left and right, with weights $0.4, 0.6$. Solve for $p_2$.