Another wierd math question...Lucie and Daryl's bike ride?

  • Thread starter Thread starter Nikki
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Nikki

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Lucie and Daryl decide to bike ride across Western Kansas. They both agreed that they would start at the same time and leave from the same point, but they would go in different directions and at different rates.
Lucie said, "I will ride straight north at a rate of 4 km per 30 min."
Daryl agreed but said, "I choose to go straight east at a rate that is 1 km more than your rate over 10 fewer minutes."
Lucie agreed and told him to be in contact by phone.
After a while, Lucie called Daryl to see if he was ok. At that time, the shortest distance between the bikers was 6.8 km. How many MINUTES after they departed was the call made?

Please explain how you got your answer. Thanks...
 
Lucy's rate = 8 km/hour; Daryl's = 5km/20 minutes = 15km/hour. Thus, the hypotenuse between the two bikers = 6.8 km; this is a pythagorean triplet (8.15, 17); simply multiply 6.8/17= .4; thus, Lucy was 3.2 km from where she started, she was going 8 km/hour, so she was 3.2/8(60) = 24 minutes into her journey when she made the call.
 
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