document.write( "Question 887930: (Question) Two cyclists start biking from a trailhead at different speeds and times. The second cyclist travels at 10 miles per hour and starts 2 hours after the first cyclist, who is traveling at 6 miles per hour. Once the second cyclist starts biking, how much time will pass before he catches up with the first cyclist?
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document.write( "(Answer)
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document.write( "(a)2 hours
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document.write( "(b)4 1/2 hours
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document.write( "(c)5 3/4 hours
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document.write( "(d)6 hours
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document.write( "(e)7 1/2 hours\r
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document.write( "My attempt: \r
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document.write( "What is known from the problem-
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document.write( "Distance formula=
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document.write( "r*t=d\r
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document.write( "1st cyclist: 3 hours and 18 miles ahead 2nd cyclist (0hr, 0mi; 1hr, 6mi; 2hr, 12mi; 3hr, 18mi)\r
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document.write( "2nd cyclist: 3 hours and 18 miles behind 1st cyclist (0hr, 0mi; 1hr, 0mi; 2hr, 0mi; 3hr, 0mi)\r
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document.write( "Cyclist 2 starts to ride after Cyclist 1 has traveled for 3 hours or 18 miles.
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document.write( "(1st hour) for 2nd cyclist = 4th hour for 1st cyclist
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document.write( "1st cyclist after 4hrs = 24 miles
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document.write( "2nd cyclist after 1hrs = 10 miles
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document.write( "(2nd hour)
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document.write( "1st cyclist after 5hrs = 30 miles
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document.write( "2nd cyclist after 2hrs = 20 miles
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document.write( "(3rd hour)
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document.write( "1st cyclist after 6hrs = 36 miles
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document.write( "2nd cyclist after 3hrs = 30 miles
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document.write( "(4th hour)
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document.write( "1st cyclist after 7hrs = 42 miles
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document.write( "2nd cyclist after 4hrs = 40 miles
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document.write( "(5th hour)
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document.write( "1st cyclist after 8hrs = 48 miles
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document.write( "2nd cyclist after 5hrs = 50 miles\r
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document.write( "Choices (c), (d), and (e) are both too long.
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document.write( "Choice (a) is too short.
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document.write( "There for choice (b) is the correct answer. \r
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document.write( "Checking the answer:
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document.write( "(4 1/2th hour)
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document.write( "1st Cyclist after 7 1/2hrs = 45 miles
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document.write( "2nd cyclist after 4 1/2hrs = 45 miles\r
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document.write( "That's fine. But what is the algebraic formula for this problem? I solved it using the process of elimination from the given answer choices. There must be a faster way?
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document.write( "
Algebra.Com's Answer #536921 by Alan3354(69443)![]() ![]() You can put this solution on YOUR website! Two cyclists start biking from a trailhead at different speeds and times. The second cyclist travels at 10 miles per hour and starts 2 hours after the first cyclist, who is traveling at 6 miles per hour. Once the second cyclist starts biking, how much time will pass before he catches up with the first cyclist? \n" ); document.write( "--------------- \n" ); document.write( "In 2 hours, the 1st cyclist is 12 miles away (2*6). \n" ); document.write( "The 2nd cyclist \"gains on\" the 1st are 4 mi/hr (10-6). \n" ); document.write( "12/4 = 3 hours. \n" ); document.write( " \n" ); document.write( " |