You're blindfolded, disoriented, and standing one mile from the Great Wall of China. How far do you have to walk to guarantee that you will run into the wall?

Assume that the wall is infinitely long and straight.

You would have to walk at most 4 miles.

Step 1:  Walk one mile in any direction.
Step 2:  Turn right 45 degrees and walk one more mile.
Step 3:  Turn right 45 degrees and walk two more miles.

You are guaranteed to hit the wall during one of the three steps above.

Posted by Joshua on 2010-08-10 14:04:52