SOLUTION: The car moves over a winding road as follows: for the first 20 minutes it travels a constant speed of 54km/h; for a further 5 minutes at 42km/h and at last 12 minutes at 84km/h. Ca

Question 957563: The car moves over a winding road as follows: for the first 20 minutes it travels a constant speed of 54km/h; for a further 5 minutes at 42km/h and at last 12 minutes at 84km/h. Calculate the average linear speed of the car

Found 2 solutions by Alan3354, macston:
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
The car moves over a winding road as follows: for the first 20 minutes it travels a constant speed of 54km/h; for a further 5 minutes at 42km/h and at last 12 minutes at 84km/h. Calculate the average linear speed of the car
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Find the total distance.
Divide by the total time.

Answer by macston(5194) (Show Source): You can put this solution on YOUR website!
(20min)(1hr/60min)(54km/hr)=18km
(5min)(1hr/60min)(42km/hr)=3.5km
(12min)(1hr/60min)(84km/hr)=16.8km
Total distance=18km+3.5km+16.8km=38.3km
Total time=20min+5min+12min=37min
Time in hours=(37min)(1hr/60min)=0.62hr
Average speed=38.3km/0.62hr=61.8km/hr
ANSWER: The average speed was 61.8 km/hr.

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