Poisson on a Shorter Interval

Sign-ups arrive at a website independently and at a constant average rate of 6 per hour, so the count in any interval follows a Poisson distribution.

What is the probability that exactly 2 sign-ups arrive in the next 20 minutes? Round to 4 decimal places.

$P(X = k) = \frac{e^{-\lambda} \lambda^k}{k!}$

(Use $e^{-1} \approx 0.36788$, $e^{-2} \approx 0.13534$, $e^{-6} \approx 0.00248$.)