Today I take my certification test to become credentialed as a junior
high math teacher in CA. I want to thank everyone who took the time
to answer questions that I had.
In reviewing my probabilities stuff last night, I stumbled upon this
interesting paradox:
Find the probability that in 5 tosses of a fair die a three appears no
times and once.
No times = 5/6* 5/6 * 5/6 * 5/6 * 5/6 = 3125 / 7776
Once = 5/6 * 5/6 * 5/6 * 5/6 * 1/6 * 5 = 3125 / 7776
I have to admit that I would not have thought that the chance of
coming up with one number was the same as coming up with no numbers.
I can see a con game growing out of this ("A math teacher goes to the
bar, pulls out a die, and says 'Let's throw the die 5 times. You pick
a number from 1 to 6. If it comes up 2 or more times, no one wins
anything. If it comes up one, I pay you a dollar. If it doesn't come
up at all, you pay me a dollar and a quarter. Wanna play??")
Henry Sun
