In a Certain Office, the Number of Typewriters That Break $a \pm \frac { b } { c } e ^ { d }$

Short Answer

In a certain office, the number of typewriters that break down during any given week is Poisson distributed with λ = 2. What is the probability that more than three typewriters break down during a week? Enter your answer in the form $a \pm \frac { b } { c } e ^ { d }$ where $\frac { b } { c }$ is reduced.