document.write( "Question 231859: If a car travels at 70mph and then 50mph for a total of 320miles in 5 hours, how many hours did it travel at each speed? \n" ); document.write( "

Algebra.Com's Answer #171587 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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If a car travels at 70mph and then 50mph for a total of 320miles in 5 hours, how many hours did it travel at each speed?
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\n" ); document.write( "Just think this through
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\n" ); document.write( "Let t = time at 70 mph
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\n" ); document.write( "(5-t) = has to be the time at 50 mph, right?
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\n" ); document.write( "Write a simple distance equation (dist = speed * time)
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\n" ); document.write( "Dist at 70 + dist at 50 = 320 mi
\n" ); document.write( "70t + 50(5-t) = 320
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\n" ); document.write( "70t + 250 - 50t = 320
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\n" ); document.write( "70t - 50t = 320 - 250
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\n" ); document.write( "20t = 70
\n" ); document.write( "t = $\"70%2F20\"$
\n" ); document.write( "t = 3.5 hrs at 70 mph
\n" ); document.write( "then
\n" ); document.write( "5 - 3.5 = 1.5 hrs at 50
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\n" ); document.write( "Prove this by finding the total dist
\n" ); document.write( "70(3.5) + 50(1.5)
\n" ); document.write( "245 + 75 = 320 mi \n" ); document.write( "

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