SOLUTION: A trip of 500 kilometres took five and a half hours to complete by car. During the first 30 minutes, travelling was slow because of heavy traffic, but for the rest of the journey,

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Question 1196500: A trip of 500 kilometres took five and a half hours to complete by car. During the first 30 minutes, travelling was slow because of heavy traffic, but for the rest of the journey, the car's speed was 10km/hr, less than twice the car's speed in heavy traffic. Determine the speed of the car in heavy traffic.
Found 2 solutions by ikleyn, josgarithmetic:
Answer by ikleyn(52775)   (Show Source):
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Let x be the slow speed (in heavy traffic), in kilometers per hour. Then the faster speed was (2x-10) kilometers per hour, according to the problem. Now write the total distance equation 0.5x + 5*(2x-10) = 500. (Here 0.5 represents 0.5 hour = 30 minutes). Simplify and find x 0.5x + 10x - 50 = 500 10.5x = 500 + 50 = 550 x = 550/10.5 = 52.381 km/h. ANSWER. The average speed in slow traffic was 52.381 km/h.

Solved.

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Answer by josgarithmetic(39616)   (Show Source):
You can put this solution on YOUR website!
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SPEEDS TIME(hours) DISTANCES Slow in Heavy Traffic r 0.5 0.5r Rest of Journey 2r-10 5 5(2r-10) TOTAL 5.5 500

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