Question 387537
You can think of the situation as 1 of the trains being
stationary and the other moving towards it at the sum of their
speeds, or {{{60 + 60 = 120}}} km/hr
The fly leaps off the stationary one at {{{80}}} km/hr. Now 
think of the fly as being stationary, and the other train
coming towards it at the sum of their speeds, 
or {{{120 + 80 = 200}}} km/hr. At that speed, the fly and the train
will meet in {{{18/200 = .09}}} hr or {{{5.4}}} min
But the trains will meet in {{{18/120 = .15}}} hr or {{{9}}} min
So, the fly gets to travel for {{{.15 - .09 = .06}}} hr at {{{120}}}
km/hr and {{{120*.06 = 8.2}}} km
I get {{{18 + 8.2 = 26.2}}} km as the distance the fly travels
I am unsure of this. I may only be half right. Check another source.