Try this out...

A affirms that B denies that C declares that D is a liar. Knowing that A, B, C and D each speak the truth once in three times (independently), figure out the probability that D was telling the truth.

Source: Sir Arthur Stanley Eddington in Volume 57 of American Mathematical Monthly, reproduced in Mathematical Medley, volume 33 no 2.

right...

if any of you who have problems remembering the quadratic formula....

Taken from Sheldon's blog:

Your Scholastic Strength Is Developing Ideas

You can take a spark of inspiration and turn it into a full fledged concept. You are talented at brainstorming, visualizing, organizing, and independent thinking. You should major in: Natural sciences Computer science Creative writing Mathematics Architecture Journalism

What Should You Major In?

logarithms....

This is the result of trying to figure out what was wrong with my powerpoint animations.





Considerably simpler than trying to figure out what was wrong in the first place. I need a mac...

interesting question...

Stef posed the following question to me:

In an exceptionally long corridor of a building, there are one thousand windows along one wall. Coincidentally, there are exactly one thousand window cleaners in the building. They've been ordered such that the first cleaner is to open the blinds on every window. Then, the second cleaner is to close the blinds on every second window. Then the third cleaner is told to go to every third window, and close the blinds if they are open, and open the blinds if they are closed. The fourth cleaner does this for every fourth window, and so on.

After all 1000 cleaners complete the process, how many blinds are open?

Interesting question! Thanks Stef. I believe the answer is 31. How I got it... well... I'm still trying to refine my answer.

I can't seem to find the solution (or even the question on the net for that matter) so I can't really verify. Anyway... those of you who like I challenge... have fun. It's not that difficult to solve... once you have the right approach.

gosh...

This is VERY lame. But highly useful, putting it up here as a resource for myself before I forget something like this actually exists; unfortunately some of the stuff is at A-lvel. Warning: listen at your own discretion.

old trick,new skin...

This is quite interesting. Well, it works but too mechanical if done without understanding. Anyone care to figure out why it works?