SOLUTION: If a car travels 1 mile at 30mph and then travels another mile at 60mph what is the average speed?....is the answer 40mph or 45mph?. Thank you

Algebra ->  Average -> SOLUTION: If a car travels 1 mile at 30mph and then travels another mile at 60mph what is the average speed?....is the answer 40mph or 45mph?. Thank you      Log On


   

Question 1057615: If a car travels 1 mile at 30mph and then travels another mile at 60mph what is the average speed?....is the answer 40mph or 45mph?. Thank you
Found 2 solutions by rothauserc, josmiceli:
Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
Using rate * time = distance, we have two formulas
:
1) t1 = 1/30
2) t2 = 1/60
:
total time t = 1 * ( 1/30 + 1/60 )
:
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average speed = (2 * 1) / ( 1 * ( 1/30 + 1/60 ) ) = 2 / ( 1/30 + 1/60 ) = 40 mph
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:

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Average speed is always
[ total distance traveled ] / [ total time spent traveling ]
----------------------
+t%5B1%5D+=+d%2Fr+
+t%5B1%5D+=+1%2F30+ hr
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+t%5B2%5D+=+d%2Fr+
+t%5B2%5D+=+1%2F60+ hr
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Average speed = +%28%28+1+%2B+1+%29%29+%2F+%28%28+1%2F30+%2B+1%2F60+%29%29+
+2+%2F+%28%28+2%2F60+%2B+1%2F60+%29%29+
+2+%2F+%28%28+3%2F60+%29%29+
+2+%2F+%28%28+1%2F20+%29%29+
+2%2A20+=+40+
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The average speed is 40 mi/hr