SOLUTION: if i average 20 miles per hour on the way to a show and 30 miles per hour on the way back what was the average speed for the whole trip?

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Question 385663: if i average 20 miles per hour on the way to a show and 30 miles per hour on the way back what was the average speed for the whole trip?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
If i average 20 miles per hour on the way to a show and 30 miles per hour on the way back what was the average speed for the whole trip?
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To the show:
rate = 20 mph ; distance = x miles ; time = x/20 hrs.
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From the show:
rate = 30 mph ; distance = x miles ; time = x/30 hrs.
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Average for the whole trip = total distance/ total time
= (2x)/[x/20 + x/30]
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= (2x)/[(30x+20x)/600]
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= (2x)/[50x/600]
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= 2x[600/50x]
= 2[12]
= 24 mph
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Cheers,
Stan H.