Some people need a math lesson.

[robbob]

11. I am constantly astounded by peoples lack of basic math skills

I discovered an interesting math puzzle the other day called the Monty Hall problem, so named because of the “Let’s Make a Deal” game show set up.

https://betterexplained.com/articles/understanding-the-monty-hall-problem/

The set up is simple. There are three doors, behind one of which is the grand prize typically “A NEW CAR!!!”

The game show host gets you to pick a door. Before opening it he goes to one of the other remaining doors and opens it to reveal a booby prize usually something of a joke like a goat. Then he asked you do you want to stay with your first guess or do you want to switch to the one remaining door.

The question is, should you stick with your original guess or switch to the remaining door that hasn’t been opened yet? Or does it even make a difference if you stay with your original guess or switch? The answer may surprise you; if you like these kind of brainteasers I highly recommend the link above. Spoiler alert! I’m going to give the answer away so if you enjoy working out a problem don’t read any further!

Anyway, I was explaining this problem to some friends one of whom is a medical doctor. She insisted that it didn’t matter if you switch or not because with two doors remaining the odds are 50-50 that the prize could be behind either door.

Here’s where I had to shake my head at the lack of math skills in an otherwise very intelligent person. To illustrate the point that you should ALWAYS switch to the remaining door I asked her, what if you started with 100 doors? You pick one door so your chances are one in 100 of having the right door and then Monty Hall opens all the other doors except for one and then asks you if you should stick with your original guess or switch.

At this point I expected a lightbulb to go on, but no, she insisted that with two doors remaining the odds of having the prize behind either door was still 50-50 and therefore it didn’t matter if you stuck with your original pick or switched. No amount of arguing could change her mind. I was absolutely flabbergasted. My conclusion was, some people get math and some don’t.