runouw.com

Seeing how a lot of people in this forum like Math, I thought "why not making a math thread?" And here it is!






Weather you need help or have a question, or want to show something cool, or want to post a math puzzle, or anything your imagine. And no, I am not coming with a math pun.


Ok, fine. If you ever wondered why, just calculate y, and if you wonder again, calculate x (or z)!

NAN




IT'S TIME

Aka the thread Nan hates. Add that to the subtitle

You should have made this thread sooner. I'm gonna face my fate in... *looks at wristwatch* 20 minutes. -_-

This thread will probably come in handy to other peoples though.

Also, now that I see you guys directly reference me like this, I feel like I'm popular. :3

when i remember about math i think of nan

so nan is popular now, because he hates math

Best of luck Nan!

So I thought I might start with a puzzle that is not very hard (just for a warm up), but it is pretty intresting, showing that probability really is something counterintuitive.

Girl or boy?
In a two-child family, one child is a boy. What is the probability that the other child is a girl? What if the older child is a boy?

EDIT: Oh, credit: mathforum.org

A very simple puzzle that, at least to me, is very intresting. It reminds me to the Monty Hall problem.

*Thumbs up to this topic* ...

... but this one is too easy. The probability for a girl or a boy stays the same no matter which sex any previous child has. Here's a slightly harder one:

Be sure not to bet too much. I show you three cards, one has two black sides, another has two red sides, and the third has both one black side and one red side. I put the cards under a hat, take one out randomly (or better: let you take one out) so that only the front side is visible, and then I bet 10 bucks that the back side has the same colour as the front side. How many bucks shall you hold up to let this be a fair bet?

20/3 bucks

Maybe you have the right idea, but I strongly believe this is incorrect

One more try.

It does affect, Shroom. Try putting it up as a traditional probability problem. The answer may surprise you.