Question 970255
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ANSWER 1:
T=Total time=Total distance/45mph=Time at 40mph + Time at 55 mph
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Distance at 40mi/hr + distance at 55 mi/hr = Total distance
Distance at 40mph=40mph(2hrs)=80 mi
Let T=total time
Total distance=(45mph)(T)
Time at 55mph=T-time at 40mph=T-2 hrs
Distance at 55mph=(55mph)(T-2 hrs)
80mi+(55mph)(T-2 hrs)=45mph(T)
80mi+55mph(T)-110mi=45mph(T)
55mph(T)-30mi=45mph(T) Subtract 55mph(T) from each side
-30mi=-10mph(T) Divide each side by -10mph
3 hours=T The total time was 3 hours
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Time at 55 mph=T-2hrs=3 hrs-2 hrs=1 hr
ANSWER 2: You traveled 1 hour at 55 mph
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CHECK:
Distance at 40mi/hr + distance at 55 mi/hr = Total distance
(40mph)(2hr)+(55mph)(1hr)=(45mph)(3hr)
80mi+55mi=135mi
135mi=135mi