Shadyrest Hospital: the Poisson Distribution

Shadyrest Hospital draws its patients from a rural area that has twelve thousand elderly residents. The probability that any one of the twelve thousand will have a heart attack on a given day and will need to be connected to a special cardiac monitoring machine has been estimated to be one in eight thousand.

Currently the hospital has three such machines. What is the probability that the equipment will be inadequate to meet tomorrow's emergencies?

Reference: An Introduction to Mathematiucal Statistics, by Larsen & Marx, 4th edition, Prentice Hall (Chapter 4.2)