What Is the Probability That 3 or More Phone Calls

Essay

What is the probability that 3 or more phone calls are received in any hour of operation?
$\begin{array}{lllll}&\text {A}&\text {B}&\text {C}&\text {D}\\&\text {\# of phone calls } & \text { P\# of phone calls)}&\text { \# of phone calls}&\text { P\# of phone calls) }\\1\\\hline2 & 1 & 0.10 & 1 & 0.10 \\3 & 2 & 0.40 & 2 & 0.50 \\4 & 3 & 0.30 & 3 & 0.80 \\5 & 4 & 0.15 & 4 & 0.95 \\6 & 5 & 0.05 & 5 & 1.00\end{array}$