Question: A Train A is approaching at a speed of 10m/sec, another Train B moving in the opposite direction at a speed of 20m/sec. A fly whose absolute speed is 50m/sec goes repeatedly from A to B and back, without loosing any time at any of the trains. The repeated moving back and forth stops when the 2 trains crash into each other. The initial distance between the 2 trains is 300m.
1>Find the distance traveled by the fly
2>Find the number of trips made by the fly back and forth
My Question: I get that the answer to the first question is 500m, since it takes 10 seconds for the 2 trains to crash, so in 10 seconds at a speed of 50m/sec the fly covers 50m/sec*10sec = 500m.
But how do I find the number of trips(back and forth) the fly makes until the trains crash?