gistfile1.txt

import random

def simulation(x):
    subjects = 0
    trials = 0
    while True:
        trials += 1
        if random.random() < 0.30:
            #Runs following code with 30% chance
            subjects += 1
            if subjects >= 3:
                return trials

def average(l):
    return sum(l)/float(len(l))

print average(map(simulation, xrange(5000000)))