Two locomotives 70 kilometers apart are travelling on the same track towards each other , Engine A moves at 22 kilometers per hour east and engine B moves at 13 kilometers per hour west. At the instant both trains begin moving, an annoying mutant fly begins flying from engine A towards engine B at 33 kilometers per hour . The instant it touches B, it turns around and flies back. It goes on this way until the two locomotives collide and the mutant fly is finally squashed. So, before its untimely demise, a) what is the total distance the fly flew? b) the time it took till it was eliminated and c) the average velocity of the fly? how can i find this please

Two locomotives 70 kilometers apart are travelling on the same track towards each other , Engine A moves at 22 kilometers per hour east and engine B moves at 13 kilometers per hour west. At the instant both trains begin moving, an annoying mutant fly begins flying from engine A towards engine B at 33 kilometers per hour . The instant it touches B, it turns around and flies back. It goes on this way until the two locomotives collide and the mutant fly is finally squashed. So, before its untimely demise, a) what is the total distance the fly flew? b) the time it took till it was eliminated and c) the average velocity of the fly? how can i find this please