I don't know how to derive the tail of cdf for this situation:
We do a Bernoulli experiment every $\frac{1}{n}$ seconds, the probability of success is $\frac{\lambda}{n}$. $Y_n$ is the waiting time for the first success, in seconds. Determine the tail of cdf of $Y_n$.
My approach I started by thinking of the distribution of $Y_n$ and came up that it is a geomterical distribution, something of the kind $$P(Y_n = k) = p(1-p)^{k-1},$$ but don't know where to put the information that it is now only every $\frac{1}{n}$ seconds. Then the tail od cdf would be 1 - cdf.