Question 511645
d = rt is the basic distance equation.
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Lauren's d = 50*t
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Jeff's d<sub>1</sub> = 60(t - 1/2)
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d + d<sub>1</sub> = 300
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50t + 60t - 30 = 300
110t = 330
t = 3 hr
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Check to ensure the distance is 300 miles.
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Lauren drives 3 hr @ 50 mph = 150 miles.
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Jeff drives 2.5 hr @ 60 mph = 150 miles.
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OK.
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Answer:  Jeff will have driven for 2 1/2 hrs when then are 300 miles apart.
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Done.