SOLUTION: joe drove a rate of 24 mph for 3 hours then he drove at 40mph for another 5 hours. What is his average speed for the entire trip?

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Question 492877: joe drove a rate of 24 mph for 3 hours then he drove at 40mph for another 5 hours. What is his average speed for the entire trip?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Average speed is always ( total distance ) / ( total time )
Is is NOT the average of 2 averages, so
+d%5B1%5D+=+24%2A3+
+d%5B1%5D+=+72+ mi
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+d%5B2%5D+=+40%2A5+
+d%5B2%5D+=+200+ mi
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The average speed is
+%28+72+%2B+200+%29+%2F+%28+3+%2B+5+%29+
+272+%2F+8++=+34+
His average speed is 34 mi/hr
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Note that the average of the averages is
+%28+24+%2B+40+%29+%2F+2+=+32+ and this is wrong