SOLUTION: Two cars leave towns at 540 Kilometers apart at the same time,and travel toward each other. One cars rate is 18 kilometers per hour less than the others. If they meet in 3 hours, w

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Question 1031572: Two cars leave towns at 540 Kilometers apart at the same time,and travel toward each other. One cars rate is 18 kilometers per hour less than the others. If they meet in 3 hours, what is the rate of the slower car?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
You can think of this as one of the cars standing
still and the other car moving at the sum of their speeds
------------------
Let +s+ = the speed of the faster car in km/hr
+s+-+18+ = the speed of the slower car in km/hr
+3+ = time in hrs until they meet
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+540+=+%28+s+%2B+s+-+18+%29%2A3+
+540+=+6s+-+54+
+6s+=+594+
+s+=+99+
and
+s+-+18+=+81+
The slower car's rate is 81 km/hr
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Check answer:
Let +d%5B1%5D+ = distance slower car travels in 3 hrs
Let +d%5B2%5D+ = distance faster car travels in 3 hrs
-----------------------
(1) +d%5B1%5D+=+81%2A3+
(1) +d%5B1%5D+=+243+ km
and
(2) +d%5B2%5D+=+99%2A3+
(2) +d%5B2%5D+=+297+ km
+d%5B1%5D+%2B+d%5B2%5D+=+243+%2B+297+
+d%5B1%5D+%2B+d%5B2%5D+=+540+ km
OK