Question 839101
At a cross-country meet, Jen jogged 8 mph for the first part of the race, then increased her speed to 12 mph for the second part. If the race was 21 miles long, and Jen completed the race in two hours, how far did she jog at the faster pace?
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Slower pace DATA:
rate = 8 mph ; time = t hrs ; distance = 8t miles
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Faster pace DATA:
rate = 12 mph ; time = 2-t hrs ; distance 12(2-t) miles
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Equation:
distance + distance = 21 miles
8t + 12(2-t) = 21
8t + 24 - 12t = 21
-6t = -3
t = 1/2 hr. (slower time)
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2-t = 1.5 hr. (faster time)
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Cheers,
Stan H.
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