SOLUTION: At 1pm your friend leaves for college traveling on the interstate at a constant speed of 65mph. At 1:24pm you realize he has forgotten some necessary things for living away at coll

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Question 126606: At 1pm your friend leaves for college traveling on the interstate at a constant speed of 65mph. At 1:24pm you realize he has forgotten some necessary things for living away at colleg. You drive after your friend maintaining a speed of 70mph. If neither of you alter your speed, how many miles will you travel before you overtake him?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
At 1 pm your friend leaves for college traveling on the interstate at a constant speed of 65 mph. At 1:24 pm you realize he has forgotten some necessary things for living away at college. You drive after your friend maintaining a speed of 70mph. If neither of you alter your speed, how many miles will you travel before you overtake him?
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Let d = distance traveled when you catch up with your friend
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Change 24 min to hrs. 24/60 = .4 hrs
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When this happens, they will have traveled the same distance (d):
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Write a time equation: Time = distance%2Fspeed
Friends time - .4 hrs = your time
d%2F65 - .4 = d%2F70
Multiply equation by 65*70 = 4550
4550*d%2F65 - 4550(.4) = 4550*d%2F70
Cancel out the denominators and you have:
70d - 1820 = 65d
70d - 65d = 1820
5d = 1820
d = 1820%2F5
d = 364 miles
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That seems like a long way. Check solution by finding the travel times
364/65 = 5.6 hr
364/70 = 5.2 hr
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differ = 0.4 hrs; confirms our solution
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Did this make sense? Did I explain it well enough?