document.write( "Question 256566: Katrina drove her car to Boston at a speed of 100 kph (kilometers per hour). She drove back at 75 kph. The total driving time was 7 hours. How far away was Boston? \n" ); document.write( "

Algebra.Com's Answer #188742 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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Katrina drove her car to Boston at a speed of 100 kph (kilometers per hour).
\n" ); document.write( " She drove back at 75 kph. The total driving time was 7 hours.
\n" ); document.write( " How far away was Boston?
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\n" ); document.write( "Let d = distance to Boston
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\n" ); document.write( "Write a time equation: Time = dist/speed
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\n" ); document.write( "To B. time + from B. time = 7 hrs
\n" ); document.write( " $\"d%2F100\"$ + $\"d%2F75\"$ = 7
\n" ); document.write( "Multiply by 300 to get rid of the denominator, results
\n" ); document.write( "3d + 4d = 300(7)
\n" ); document.write( "7d = 2100
\n" ); document.write( "d = $\"2100%2F7\"$
\n" ); document.write( "d = 300 mi to B.
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\n" ); document.write( "Check solution, find the time of each trip
\n" ); document.write( "300/100 = 3 hrs
\n" ); document.write( "300/75 = 4 hrs
\n" ); document.write( "---------------
\n" ); document.write( "total = 7 hrs
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\n" ); document.write( "That's pretty easy, right?
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