> > If you notice the whole thing lasts 2 hours, you see at once the > answer is 150 miles. > But you might instead work out that the first leg of the fly's > trip lasts 1.6 hours and is 120 miles long; the second leg is 1/5 as > long, 24 miles; the third, likewise, is 4.8 miles; and so on. You sum > the infinite series (a geometric one)... and get 150 miles, the hard way.
Yes, it is rather simple:
s1*SUM(C^n,n=1,oo) where C = V1/V2 (If you have one train as a refernece point)
> > The story goes, someone gave this to von Neumann and the latter gave > the answer in a few seconds. > -- "Ah, of course you saw the quick method... You know, some people > try to sum the infinite series..." > -- "What do you mean?... I _did_ sum the infinite series..." > >