Math Is Fun Forum

Hello my purveyors, I have an enigma that is unfortunately perplexing to me...
The archer wants to show his exemplary skill to his friends, so he takes on the challenge of shooting an arrow through the opposing windows of a train that's moving at 120 feet per second. Standing on a platform, the archer shoots. Luckily for him, the arrow reaches the upper right corner of a window(from his vantage point), and the arrow manages to exit through the opposing window's lower left corner(from his vantage point).
Dimensions: The top of the train is 15 ft from the railroad tracks and the tops of each window are 5 ft away from the top of the train. Each window measures 5ft by 24 ft. The (i.e, vertical)perpendicular distance between both opposing windows is 12 ft.
Questions:
If the arrow took 4 seconds to reach the upper right corner of the first window, what were a) the archer's horizontal distance from the train; b) the height of the platform on which he was standing on, if he was standing vertically when he fired the arrow from his shoulder(shoulder height is 5.5 ft). Finally, find c) the time, in seconds, it took for the arrow to hit the ground the moment the arrow left the train(express this in a fraction.)
Neglect all effects of friction, air resistance, drag, and all components of physics that would be problematic. In other words, treat everything as if they were merely points in space, and assume the arrow travelled linearly.

I have perused the problem several times, and it seems to utilize similar triangles and other interesting triangles.( the arrow travels at 65 ft/sec, though my explanation is handwaving.)

I would appreciate a solution from our sagacious members.
-Mathe