SOLUTION: the average speed of the local train is 10 miles per hour less than two-thirds the speed of the express train. the local train leaves at noon. the express train leaves at 1:00 pm,

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Question 1020503: the average speed of the local train is 10 miles per hour less than two-thirds the speed of the express train. the local train leaves at noon. the express train leaves at 1:00 pm, from the same station and travels in the same direction as the local train on a parallel track. if the express train overtakes the local train at 2:00 pm, what is the speed of each train?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +s+ = the speed in mi/hr of the express train
+%282%2F3%29%2As+-+10+ = the speed of the local train
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From noon to 1 PM is 1 hr. How much of a headstart
in miles does the local train have?
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+d%5B1%5D+=+%28%282%2F3%29%2As+-+10+%29%2A1+
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Time both trains starting at 1 PM to 2 PM
Let +d+ = the distance in miles the express train travels
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Equation for local train:
(1) +d+-+%28%282%2F3%29%2As+-+10+%29+=+%28%282%2F3%29%2As+-+10+%29%2A1+
Equation for express train:
(2) +d+=+s%2A1+
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(1) +d+=+2%2A%28+%282%2F3%29%2As+-+10+%29+
(1) +d+=+%284%2F3%29%2As+-+20+
Substitute (2) into (1)
(1) s+=+%284%2F3%29%2As+-+20+
Multiply both sides by 3
(1) +3s+=+4s+-+60+
(1) +s+=+60+
(1) +%282%2F3%29%2As+-+10+=+%282%2F3%29%2A60+-+10+
(1) +%282%2F3%29%2As+-+10+=+40+-+10+
(1) +%282%2F3%29%2As+-+10+=+30+
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The local train's speed is 30 mi/hr
The express train's speed is 60 mi/hr
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check:
+d%5B1%5D+=+%28%282%2F3%29%2As+-+10+%29%2A1+
+d%5B1%5D+=+%28%282%2F3%29%2As+-+10+%29%2A1+
+d%5B1%5D+=+30+
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(1)
(1) +d+=+60+
and
(2) +d+=+s%2A1+
(2) +60+=+s+
OK