Question 344699
a train leaves the station at 1 pm. it travels at a rate of 72 mph.
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DATA:
rate = 72; time = x hrs. ; distance = 72x miles
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another train leaves the same station an hour later. it travels at rate of 90 mph the second train follows the same route as the first, on a track parallel to the first.
DATA:
rate = 90 mph ; time = x-1 hr. ; distance = 90(x-1) miles
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how long will it take the second train to catch up to the first?
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Equation:
distance = distance
72x = 90(x-1)
72x = 90x-90
18x = 90
x = 5 hrs 
x-1 = 4 hrs (time it will take the 2nd train to catch the 1st train)
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Cheers,
Stan H.