Question 58065
A man travels from one city to another at the rate of 40 mph. He returns at the rate of 60 mph. if the trip takes 8 hours, how far apart are the citys? 
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"To the city DATA"
rate=40 mph ; distance = x miles ; time = d/r = x/40 hrs.
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From the city DATA"
rate=60 mph ; distance = x miles ; time = d/r = x/60
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EQUATION:
time to + time from = 8 hrs
x/40 + x/60 = 8
Multiply thru by 2400 to get:
60x + 40x = 8*2400
100x=19200
x=192 miles (distance between the cities)
Cheers,
Stan H.