SOLUTION: I've been stuck on this question for awhile and I'm confused: Two families are traveling by car to a camp 280 kilometers away. One family leaves 20 minutes ahead of the other fa

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Question 93572: I've been stuck on this question for awhile and I'm confused:
Two families are traveling by car to a camp 280 kilometers away. One family leaves 20 minutes ahead of the other family and travels at an average speed of 40 kilometers per hour. What would the speed of the second family's car need to be if the family is to reach the camp at the same time as the first family?
They give me a hint here: (Set up the equation and solve by substitution.)
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Two families are traveling by car to a camp 280 kilometers away.
One family leaves 20 minutes ahead of the other family and travels at an average speed of 40 kilometers per hour.
What would the speed of the second family's car need to be if the family is to reach the camp at the same time as the first family?
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1st family DATA:
Rate = 40kph ; distance = 280 km ; time = d/r = 7 hrs
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2nd family DATA:
Time = x hrs ; Distance = 280 km ; Rate = d/t = 280/x kpm
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EQUATION:
1st car time - 2nd car time = (1/3) hr
7 - x = 1/3
x = 20/3 hrs
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Then Rate of 2nd car = 280/x = 280/(20/3) = 14*3 = 42 kpm
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Cheers,
Stan H.




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Rate of the 2nd car is 42 kph
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Cheers,
Stan H.