Question 284368
Let x = Hours the train travels
Thefore, x-1 = Hours the bus travels.

Since the distances are the same, equate the two sets of hours.

{{{40x = 50(x-1)}}}
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{{{40x = 50x - 50}}}
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{{{-10x = -50}}}
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{{{x = highlight(5)}}}
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Proof:  
The train travels 5 hours * 40 MPH = 200 miles
the bus travels 4 hours * 50 MPH = 200 miles.