SOLUTION: it took Betty 4.5 hours to drive to her mother's house on monday morning. on her return trip on Tuesday night, traffic was heavy, so the trip took her 5 hours. her average speed on

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Question 956735: it took Betty 4.5 hours to drive to her mother's house on monday morning. on her return trip on Tuesday night, traffic was heavy, so the trip took her 5 hours. her average speed on Tuesday was 4 mph slower than on Mondays.What was her average speed on Tuesday?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
it took Betty 4.5 hours to drive to her mother's house on monday morning. on her return trip on Tuesday night, traffic was heavy, so the trip took her 5 hours. her average speed on Tuesday was 4 mph slower than on Mondays.What was her average speed on Tuesday?
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Monday DATA:
time = 4.5 hrs ; rate = r mph ; distance = 4.5r miles
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Tuesday DATA:
time = 5 hrs ; rate = r-4 mph ; distance = 5(r-4) miles
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Equation:
distance = distance
4.5r = 5r - 20
0.5r = 20
r = 40 mph (rate on Monday)
r-4 = 36 mph (rate on Tuesday)
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Cheers,
Stan H.
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