Two trains, A and B, leave their respective starting points at the same time and travel in opposite directions. They travel at constant speeds, and pass at point M. One travels at twice the speed of the other. If one of the trains leaves five minutes late they pass at a point 2 miles from point M.
What is the speed of the slow train, in miles per hour?
Given d = late distance (in miles), t = late time (in minutes),
1. Late speed = (late distance / late time)..miles per min
2. Slow Train speed = 1.5 * late speed
3. Fast Train speed = 2 * Slow train speed
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In the given equation, d = 2 miles, t = 5 minutes,
1. Late speed = 2/5 = 0.4 miles per min = 0.4*60 mph = 24 mph
2. Slow Train speed = 1.5 * 24 = 36 mph
3. Fast Train speed = 2 * 36 = 72 mph
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I suggest the readers to derive the proof!
General Shortcut Formula
