SOLUTION: You must drive to an important meeting in a nearby city. If you were to drive at 90 miles an hour, you would arrive an hour early but if you drove at 30 miles an hour, you would ar

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Question 948352: You must drive to an important meeting in a nearby city. If you were to drive at 90 miles an hour, you would arrive an hour early but if you drove at 30 miles an hour, you would arrive an hour late. At which (constant) speed should you drive so as to arrive exactly on time?
Answer by lwsshak3(11628) About Me  (Show Source):
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You must drive to an important meeting in a nearby city. If you were to drive at 90 miles an hour, you would arrive an hour early but if you drove at 30 miles an hour, you would arrive an hour late. At which (constant) speed should you drive so as to arrive exactly on time?
***
let x=distance traveled
travel time=distance/speed
x%2F30-x%2F90=2
lcd:90
3x-x=180
2x=180
x=90 miles
x/30=3 hrs (1-hr late)
x/90=1 hr (1-hr early)
To arrive exactly on time, travel time must be 2 hrs
90/2=45 mph
At which (constant) speed should you drive so as to arrive exactly on time? 45 mph