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Susan travels by car at an average speed of 50 miles per
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24 Nov 2017, 20:39
24 Nov 2017, 20:39
Expert Reply
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Question Stats:
94% (00:50) correct
5% (01:24) wrong based on 78 sessions
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Susan travels by car at an average speed of 50 miles per hour for 4 hours and then at an average speed of 20 miles per hour for 2 hours. What is her average speed, in miles per hour, for the entire 6-hour trip?
A. 25
B. 30
C. 35
D. 40
E. 45
A. 25
B. 30
C. 35
D. 40
E. 45
Drill 1
Question: 4
Page: 521
Question: 4
Page: 521
Re: Susan travels by car at an average speed of 50 miles per
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02 Dec 2017, 10:55
02 Dec 2017, 10:55
sandy wrote:
Susan travels by car at an average speed of 50 miles per hour for 4 hours and then at an average speed of 20 miles per hour for 2 hours. What is her average speed, in miles per hour, for the entire 6-hour trip?
A. 25
B. 30
C. 35
D. 40
E. 45
A. 25
B. 30
C. 35
D. 40
E. 45
Drill 1
Question: 4
Page: 521
Question: 4
Page: 521
Here in the first part,
Distance = speed * Time
Distance = 50 * 4 = 200 miles (Speed = 50 miles per hour ; Time = 4 hrs)
in the second part
Distance = 20 * 2 = 40 miles (Speed = 20 miles per hour ; Time = 2 hrs)
Therefore Total distance = 240 miles.
Av speed for the entire trip = 240/6 = 40 miles per hour (Since total time = 6 hrs)
Re: Susan travels by car at an average speed of 50 miles per
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09 Dec 2017, 19:45
09 Dec 2017, 19:45
Expert Reply
Explanation
Use the given averages to figure out Susan’s total distance: 4 hours at an average speed of 50 miles per hour is a total of 200 miles, and 2 hours at an average speed of 20 miles per hour is a total of 40 miles.
Susan goes a total of 240 miles in 6 hours, thus, her average speed is \(\frac{240}{6}\) miles/hour, or 40 miles per hour.
The answer is choice D.
Use the given averages to figure out Susan’s total distance: 4 hours at an average speed of 50 miles per hour is a total of 200 miles, and 2 hours at an average speed of 20 miles per hour is a total of 40 miles.
Susan goes a total of 240 miles in 6 hours, thus, her average speed is \(\frac{240}{6}\) miles/hour, or 40 miles per hour.
The answer is choice D.
