Probability in the Pool. Due March 4, 2015

I like to swim. When I'm visiting my dad in Connecticut, I swim mostly alone in a pool that is  50 meters by 25 meters.  Sometimes the lane lines were set to allow swimmers to swim "short course" (25 meters) or "long course" (50 meters).

On one of the short course days, I was alone in the pool.  There were 16 empty lanes.  I chose lane 8, one of the middle lanes.  I swam down-and-back (50 meters) in about 45 seconds.  This became a deliciously long swim as I moved back and forth alone in this pool with my own personal lifeguard.  Then, suddenly, I was jerked out of my fraction-calculating delirium (yeah, I practice fractions when I swim long distances) when waves overtook me.  A corpulent gentleman dropped himself and his furry belly into the lane next to mine at precisely the moment I was at his end of the pool.

Ah, I thought.  A probability problem.  (Notice I'm still in the realm of fractions!) What is the probability that he would (a) choose the lane next to mine and at the same time (b) choose to enter the water during the roughly 7 seconds that I am vulnerable to the tsunami he created at the near end of the pool?  And is this probability small enough that I should think this individual inconsiderate?

What if the lanes were set to be "long course" and the furry, corpulent gentleman deposited himself next to me during the 7 seconds I was at *that* end of the pool?  There are 9 lanes in this case; I'm in the middle lane.  It now takes 90 seconds for me to travel down-and-back. What's the probability that, if his entry is random, he would create his tsunami when it would disturb my swimming?

Well, now, TPC students, here's  your task. You can either choose to address the probability problems posed in this blog or you can choose to create your own solvable probability problems that you see in your daily life.

Have fun, as always.  Be sure your work is original (don't just copy someone else's work) and includes some significant thought. I encourage you to write something meaningful or real to you.   Feel free to be poetic or funny.