<p>It took you 10 seconds? Wow some people can be so stupid. I took 3 secs to read the problem. I knew that 7-24-25 was a Pythagorean triple before I even finished the problem. It took me about 2-3 secs to realize that 15-20-25 was another form of the 3-4-5 triple. And another second of so to calculate 15-7 and click the answer. This question should take you 7 seconds, maybe 8 seconds tops. Or else you have no hope for a 800.</p>