need help finding average speed (word problem)

mathquestioner

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Mar 9, 2008
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Hi,

I'm having touble with the following word problem:

A car traveled 10 miles at an average speed of 20 miles per hour and then traveled the next 10 miles at an average speed of 40 miles per hour. What was the average speed, in miles per hour, of the car for the 20 miles?

Of course I'm tempted by the idea that it was an average speed of 30 miles per hour, but I know it can't be that simple. Can anyone help? I'm not sure how to approach this.

Thanks very much.
 
>A car traveled 10 miles at an average speed of 20 miles per hour and then traveled the next 10 miles at an average speed of 40 miles per hour. What was the average speed, in miles per hour, of the car for the 20 miles?

Dist = rate X time, so rate = Dist/time.

So, can you figure out the total distance travelled and divide that by the total amount of time it took to travel that distance? I think that will give you your answer.
 
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