document.write( "Question 884415: Pa got in his '27 ford and started driving west from Memphis at a constant speed of 40 mph. An hour later ma got in her '34 Buick and started driving west from Memphis at a constant speed. After driving 4 hours ma had passed pa and was 20 miles ahead of him. How fast was ma driving?
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Algebra.Com's Answer #534363 by ankor@dixie-net.com(22740)\"\" \"About 
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Pa got in his '27 ford and started driving west from Memphis at a constant speed of 40 mph.
\n" ); document.write( " An hour later ma got in her '34 Buick and started driving west from Memphis at a constant speed.
\n" ); document.write( " After driving 4 hours ma had passed pa and was 20 miles ahead of him. How fast was ma driving?
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\n" ); document.write( "From the information given, Pa's travel time = 5 hrs, Ma's = 4 hrs
\n" ); document.write( "Let s = Ma's driving speed
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\n" ); document.write( "4s - 20 = 5(40)
\n" ); document.write( "4s = 200 + 20
\n" ); document.write( "s = 220/4
\n" ); document.write( "s = 55 mph is Ma's speed
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\n" ); document.write( "See if that checks out, find the distance each traveled
\n" ); document.write( "4 * 55 = 220
\n" ); document.write( "5 * 40 = 200
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\n" ); document.write( "differ: 20 mi
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