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A passenger trains speed is 60 mi/h, and a freight trains speed is 40 mi/h. The passenger train travels the same distance in 1.5 h less time than the freight train. How long does each train take to make a trip?
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Let L be the travel distance (now unknown).
Then the passenger train spends hours to cover this distance, while
the freight train spends hours.
According to the condition, the difference of these times is 1.5 hour. It gives you an equation
- = 1.5.
Multiply both sides by 40*60 to get off denominators. You will get
60*L - 40*L = 40*60*1.5, or
20*L = 3600.
Hence, L = = 180 km.
Then the passenger train spends = 3 hours, while the greight train spends = 4.5 hours.
The problem is solved.