Hello,

The number of payouts of i follows a Poisson process with a rate of 5/2^i per hour, since there are ~ 5 payouts an hour and that for each of these, there is a probability of 1/2^i that it is a payout of i.

So we have, for a given i, the probability of having k payouts of i in an amount of time equal to t : , where

Now compute this probability for i=1 and 4, k=0 and t=1/6, since 10 minutes = 1/6 hour.