Question 398210
Aya rode her bicycle from her house to a friend's house, averaging 16 kilometers per hour. It turned dark before she was ready to return home, so her friend drove her home at a rate of 80 kilometers per hour. If Aya's total traveling time was three hours, how far away did her friend live? 
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To DATA:
rate = 16 km/hr ; distance = x km ; time = d/r = x/16 hrs
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From DATA:
rate = 80 km/hr ; distance = x km ; time = d/r = x/80 hrs
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Equation:
time + time = 3 hrs
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x/16 + x/80 = 3
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Multiply thru by 80 to get:
5x + x = 240
6x = 240
x = 40 km (distance to her friend's house).
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Cheers,
Stan H.