SOLUTION: Hi I don't understand how to set up this problem. During the first 20 mi of a 50 mi bicycle race, Roger's average speed was 16 mi/h. What must his average speed be during the remai
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Question 780035: Hi I don't understand how to set up this problem. During the first 20 mi of a 50 mi bicycle race, Roger's average speed was 16 mi/h. What must his average speed be during the remainder of the race if he is to finish the race in less than 2.5h? Found 2 solutions by lwsshak3, stanbon:Answer by lwsshak3(11628) (Show Source):
You can put this solution on YOUR website! Hi I don't understand how to set up this problem. During the first 20 mi of a 50 mi bicycle race, Roger's average speed was 16 mi/h. What must his average speed be during the remainder of the race if he is to finish the race in less than 2.5h?
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let x= Roger's average speed during remainder of the race
travel time=distance/speed
LCD:4x
5x+120=10x
5x=120
x=24
Roger's average speed during remainder of the race=24 mph
You can put this solution on YOUR website! During the first 20 mi of a 50 mi bicycle race, Roger's average speed was 16 mi/h. What must his average speed be during the remainder of the race if he is to finish the race in less than 2.5h?
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1st leg DATA::
distance = 20 mi ; rate = 16 mph ; time = d/r = 20/16 = 5/4 hr.
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Total journey DATA:
distance = 50 mi ; time = 2.5hr ; rate = 50/2.5 = 20 mph
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2nd leg DATA:
distance = 30 mi ; time = (5/2)-(5/4) hr = (5/4) hrs
Equation:
2nd leg rate:
rate = distance/time = 30 mi/(5/4)hr = 120/5 = 24 mph
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Cheers,
Stan H.
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