document.write( "Question 602915: To get to work, you drive for 20 minutes at 30 mph, and walk 10 more minutes at 3 mph. What was your average speed?\r
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\n" ); document.write( "\n" ); document.write( " a) 16.5 mph
\n" ); document.write( " b) 20 mph
\n" ); document.write( " c) 21 mph
\n" ); document.write( " d) 23 mph
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Algebra.Com's Answer #380492 by ewatrrr(24785) $\"\"$ $\"About$

You can put this solution on YOUR website!

 
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document.write( "Hi,
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document.write( "Note D = r*t   20min = 1/3 hr and 10min = 1/6 hr
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document.write( "(1/3hr)30mph + (1/6hr)3mph = 10.5 mi, the total distance traveled.
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document.write( " total distance / total time = average speed = 10.5/(1/3 + 1/6) = 10.5/(2/6 + 1/6)
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document.write( "10.5mi/.5hr = 21mph \n" );
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