document.write( "Question 545713: andy's average driving speed for a 4 hour trip was 45 miles per hour. during the first 3 hours he drove 40 miles per hour. what was his average speed for the last hour on his trip?
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Algebra.Com's Answer #355683 by smmoore(10) $\"\"$ $\"About$

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the question is asking for the average speed of the last hour. we know that the average speed for the whole 4 hour trip is 45mph, and the average speed for three of the hours is 40mph. an average is all the numbers added together, then divided by the number of numbers. \\r
\n" ); document.write( "\n" ); document.write( "the first 3 hours: 40+40+40 which equals 120, then to find the mean, we divide the sum by3. to see what the total sum for all 4 hrs we multiply 45(average) by 4. that equals 180. \r
\n" ); document.write( "\n" ); document.write( "next we do 180-120 which equals 60. so the average speed driven for the 4th hour is 60 miles per hour\r
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