Wednesday, August 18, 2010

Easy? Hard? Math Quiz

image via bitte ein kuss
Apropos nothing except whatever, what is the next number in the series?

0.5000, 0.1667, 0.0833, 0.0500, 0.0333, 0.0238, .0179, ....

I ask because I feel like it and because it's one of those little math puzzles I spin out in my head and then immediately lose perspective on whether it's hard or easy.

Note: the image is not a hint. It's just awesome.

The answer appears in a comment to this post. If you cheat, the terrorists have already won.

1 comment:

Dale said...

First picture this series of familiar everyday numbers -- I, for one, use them almost daily.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10

Then consider the inverse of each:

1/1, 1/2, 1/3, 1/4, 1/5, 1/6, 1/7, 1/8, 1/9, 1/10.

Each of the first series of numbers is spaced exactly equally apart. 1+1=2, 2+1=3, 3+1=4, etc.

Not so the second list!

0.5000 = 1/1-1/2
0.1667 = 1/2-1/3
0.0833 = 1/3-1/4

... and so on. Therefore the next two in the series are these:

0.0139 = 1/8-1/9
0.0111 = 1/9-1/10

Neat.