A fifteen feet long ladder is placed across a street such that while its base is at one edge of the street its top rests against the opposite wall at a height of nine feet. Similarly, another ladder, twenty feet long, is placed resting across the other side-wall so that the two ladders cross each other. A spider wishing to cross the street, climbs up one ladder till it gets to the meeting point; thereafter, it climbs down the other.

How long will the spider take to accomplish the crossing assuming that he covers a foot in ten seconds?

I also saw the 3-4-5 right triangle pattern and solved it that way, and agree with Patrick's walk through and solution.  Of course if you want to make it hard on yourself, you could use the sine/cosine method of solving it.

Posted by Dave Soderstrom on 2006-07-12 20:11:52