A car drives for 20 miles total. The first 10 miles were at 30mph and the next 10 miles were at 50 mph. What is the average speed? Thank you.
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avg speed = total distance/total time
we know the total dist is 20 miles
we need to find the time:
in the first segment, time = dist/speed = 10 miles/30mi/hr = 1/3 hr = 20 mins
in the second segment, time = 10mi/50mi/hr = 1/5 hr = 12 mins
the total time is 32 mins or 0.53hr
therefore, avg speed = 20mi/0.53hr = 37.7 mi/hr
we know the total dist is 20 miles
we need to find the time:
in the first segment, time = dist/speed = 10 miles/30mi/hr = 1/3 hr = 20 mins
in the second segment, time = 10mi/50mi/hr = 1/5 hr = 12 mins
the total time is 32 mins or 0.53hr
therefore, avg speed = 20mi/0.53hr = 37.7 mi/hr
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The average speed is 45mph