## Monday, March 31, 2008

### Walk half of the distance

You are in a large hall. There is a pretty girl at the other end of the hall. You are old that it takes 10 seconds to walk half of the distance to the girl, another 10 seconds to walk half of the remaining distance, another 10 seconds to walk half of the remaining distance, and so on. How long will it take you to reach the girl?

Most people will say that you will never reach the girl. No matter where you are, it will take 10 seconds to walk half of the remaining distance.

Anonymous said...

Like you have said, it is almost impossible to reach that girl.

jeff said...

Give me 1 minute and I will get close enough for all practical purposes.

(Naughty naughty)

Anonymous said...

Scientifically, the old man will never reach the girl it will reach the "~". But socially, with the distance, the old man can start the communication with the girl already.

Rhincodon said...

Assuming the hall is 100m long and we're on opposite ends, it will take approximately 1.5 min.

50.0m - 10sec
25.0m - 10sec
12.5m - 10sec
7.5m - 10sec
3.75m - 10sec
1.875m - 10sec
0.9375m - 10sec
0.46875m - 10sec
0.234375m - 10sec
-----------------
Total: 90sec

I think 23cm is a reasonable distance to stop in front of her without freaking her out, haha.

Tan Kin Lian said...

Jeff has got the right answer, down to the exact words!

This is supposed to be the hallmark of an actuary, who is a practical person (and not theoretical).

Ching said...

This original puzzle was first posed by a professor to his students. He wanted to find out who were the future engineers (practical guys) and who are the researchers (theoretical ones)