SOLUTION: A driver took a​ day-trip driving at two different speeds. He drove 60 miles at a slower speed and 240 miles at a speed 30 miles per hour faster. If the time spent during the
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Question 1038366: A driver took a day-trip driving at two different speeds. He drove 60 miles at a slower speed and 240 miles at a speed 30 miles per hour faster. If the time spent during the faster speed was twice that spent at a slower speed, find the two speeds during the trip. Found 2 solutions by jorel555, Boreal:Answer by jorel555(1290) (Show Source):
You can put this solution on YOUR website! Let n be the slower speed. Then
2(60/n)=240/n+30
120/n=240/n+30
120(n+30)=240n
120n+3600=240n
120n=3600
n=30
n+30=60!!!!!!!!!!!
You can put this solution on YOUR website! slow speed is x mph for y hours, so the distance is xy miles=60. y=60/x
faster speed is (x+30)mph for 2y hours, so the distance is 2xy+60y miles=240, y(2x+60)=240, y=240/(2x+60)
Set the y's equal
60/x=240/(2x+60)
cross multiply
120x+3600=240x
120x=3600
x=30 mph
2 hours to go 60 miles, so y = 2
x+30 mph=60 mph. For 4 hours (2 more), and that is 240 miles
That checks.
The speeds were 30 and 60 mph.
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