A friend posed the following problem: If you do your laundry with 18 unique pairs of socks, and you randomly grab 15 individual socks out of the dryer, what is the chance that you will not have any pairs? I created this project to simulate this situation. Just click the Green Flag to run the simulation, over and over. (Want to make the simulation run faster? Hide the list monitors by clicking the "run faster" button.)
Thanks to Ken Loveday for posing this problem. I ran 100,000 trials, and there were no pairs 474 times (0.47%). An even rarer occurrence was to get 7 pairs. That happened only 12 times in 100,000 trials (0.012%).