Pair work Ch 4.2–4.3

Problem 1

This is based on Problem 4.3.7 in the book.

Vampires can each convert v people a day into vampires. However, there is a band of vampire hunters that can kill k vampires per day. If a coven of vampires starts with vampires members, how many days before a town with a population of people becomes a town with no humans left in it? Write a function

vampireApocalypse(v, k, vampires, people)

that returns the answer to this question. The function should also plot the number of days (x-axis) versus the population of people and the population of vampires (y-axis). You'll need a separate pyplot.plot statement for each of the two populations. Give each a label, e.g.,: pyplot.plot(days, people, label='People'). You'll also need to tell pyplot to show the legend: pyplot.legend().

Try your function with this call: 

vampireApocalypse(.5, 1, 5, 40000)