Adam and beth each drove from smallville to crown city by different routes. Adam drove an average speed of 40 mph and completed the trip in 30 minutes. beth route was 5miles longer, and it took her 20 minutes more than adam to complete the trip how many miles per hour was beth 's average speed on this trip?
answer 30
please explain
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- jayhawk2001
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Total distance covered by Adam = 40 mph * 30 / 60 min = 20 miles
Beth's distance = 20 + 5 = 25 miles
Beth covers this distance in 30 + 20 = 50 minutes
If 50 minutes => 25 miles, then 60 minutes = 25 / 50 * 60 = 30 mph
Hence Beth's average speed was 30 miles per hour
Beth's distance = 20 + 5 = 25 miles
Beth covers this distance in 30 + 20 = 50 minutes
If 50 minutes => 25 miles, then 60 minutes = 25 / 50 * 60 = 30 mph
Hence Beth's average speed was 30 miles per hour
Thank you, but accoding to the distance formula its
rate * time = distance why do you divide by sixty minutes?
also,
total distance / total time = average speed, why did you divide total distance by 60 min and 50 min.
Im even more confused..could someone explain this to me. I dont want to catch this question on the real GMAT with different numbers and not know exactly how to attack this question...
rate * time = distance why do you divide by sixty minutes?
also,
total distance / total time = average speed, why did you divide total distance by 60 min and 50 min.
Im even more confused..could someone explain this to me. I dont want to catch this question on the real GMAT with different numbers and not know exactly how to attack this question...
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- Scott@TargetTestPrep
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Since Adam drove 30 minutes, or 1/2 hour, at an average speed of 40 mph, he drove 1/2 x 40 = 20 miles. Since Beth's route was 5 miles longer, she drove 25 miles. She also drove 20 minutes longer than Adam, so she drove for 50 minutes, or 5/6 hour. Thus, her average speed wasyvonne12 wrote:Adam and beth each drove from smallville to crown city by different routes. Adam drove an average speed of 40 mph and completed the trip in 30 minutes. beth route was 5miles longer, and it took her 20 minutes more than adam to complete the trip how many miles per hour was beth 's average speed on this trip?
25/(5/6) = 25 x 6/5 = 30 mph
Answer: 30
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