Two trains, each 400 ft long, run in parallel tracks. When running in the same direction, they pass in 20 sec; when running in opposite direction, they pass in 5 sec. Find the speed of each train.

Answer 1

400 feet in 20 seconds going in the same direction

in 5 seconds they "pass" in opposite directions

Not certain, but for what it's worth here's a possible solution: 10 ft/sec for slower, 30 ft/sec for faster tram

20(x+y) -20y) = 400

20x+ 20y -20y = 400

20x = 400

x= 20 ft/sec faster for the faster tram

5(x+y) -5(x) = 400 divided by 2 divided by 20/5

5x+5y -5x = 50

5y = 50

y = 10 ft.sec for slower train

y+x = 30 ft sec for faster train

(30-10) = 20 ft/sec times 20 sec = 400 feet

30+10 = 40 ft/sec times 5 seconds = 200 feet, which is half 400 because the trains are moving in opposite directions, so it only takes half the distance to pass.

Not certain I understand the problem, but maybe this is the solution.