SOLUTION: 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 e

Algebra ->  Systems-of-equations -> SOLUTION: 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 e      Log On


   



Question 1015578: 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?
Answer by ikleyn(52832) About Me  (Show Source):
You can put this solution on YOUR website!
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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 L%2F60 hours to cover this distance, while
the freight train spends L%2F40 hours.

According to the condition, the difference of these times is 1.5 hour. It gives you an equation

L%2F40 - L%2F60 = 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 = 3600%2F20 = 180 km.

Then the passenger train spends 180%2F60 = 3 hours, while the greight train spends 180%2F40 = 4.5 hours.

The problem is solved.