Strange Poisson Problem

Jul 2010
I'm stuck with a very strange problem at hand and need an urgent solution.

A speciality hospital caters to patients a particular type of disease only. There are 4 types of manifestations of the disease which take different time to cure.

Type No. of days of stay in the Hospital (bed occupancy days)
A 3
B 7
C 15
D 24

What should be the number of beds in the hospital so that 99% of the cases, a patient is not denied admittance?

Quick solutions will be highly appreciated. I have a presentation in 3 hours!

Thanks in advance !


MHF Helper
Sep 2008
Is this all the information you are given?

What makes you think this is Poisson?
Jul 2010
the number of people coming in will be a poisson process.
Sadly but yes, this is all the information given.

I've been trying to approach the problem.
POISSON (x, mean, cumulative) : POISSON(no of beds, (Avg No of ppl coming in per day * Avg service time in the hospital), TRUE)

But I don't have any information about the avg no of people coming in per day.