A farmer wants to catch a pig which is 100 meters away from him. They start running at the same time. The pig runs straight ahead, initially perpendicular to the line farmer-pig, at constant speed. The farmer always runs in the direction where he sees the pig (also at constant speed).

If the ratio of the speeds is 3:1 (farmer:pig), how far would the pig have traveled till the farmer caught it?

(In reply to re: Analytical Solution by Charlie)

you are quite right, I reviewed my solution and I made a slight miscalculation and when repaired I get an answer that agrees with the numerical solution of 37.5.

As for my method of getting the differential equation, I'm not very good at getting mathematical symbols to look good on here so I will simply point you to this link.  I used a modified version of this approach to get a general solution for when the farmer starts a distance d from the pig and the ratio of the speed of framer to pig is r, then I find the distance traveled by the pig is found by r*d/(r^2-1)

Posted by Daniel on 2008-11-19 09:27:55