document.write( "Question 118052: Two cars started from the same point and traveled on a straight course in
\n" ); document.write( "opposite directions for exactly 2 hours, at which time they were 208 miles
\n" ); document.write( "apart. If one car traveled, on average, 8 miles per hour faster than the other
\n" ); document.write( "car, what was the average speed for each car for the 2-hour trip?\r
\n" ); document.write( "\n" ); document.write( "I set up two equations A and B being rates in MPH
\n" ); document.write( "equation 1-- multiplied times 2 to get it A and B in distances instead of rate.
\n" ); document.write( "equation 2-- set this equation to get the relationship between rates\r
\n" ); document.write( "\n" ); document.write( "Equation 1: 2A+2B=208
\n" ); document.write( "Equation 2: A=8+B \r
\n" ); document.write( "\n" ); document.write( "then solved by plugging Equation 2 into Equation 1\r
\n" ); document.write( "\n" ); document.write( "got B = 23 and A = 31
\n" ); document.write( "which according to my answer key is not right, it says 48 and 56. I am missing some stupid detail somewhere can you help me out. It doesn't matter which is A or B. Thanks a lot for your help
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Algebra.Com's Answer #86127 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
Let x=speed of first car, y=speed of second car\r
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\n" ); document.write( "\n" ); document.write( "You're on the right track since you have the correct equations set up\r
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\n" ); document.write( "\n" ); document.write( "Start with the given system\r
\n" ); document.write( "\n" ); document.write( "\"2x%2B2y=208\"
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\n" ); document.write( "\n" ); document.write( "\"2%288%2By%29%2B2y=208\" Plug in \"x=8%2By\" into the first equation. In other words, replace each \"x\" with \"8%2By\". Notice we've eliminated the \"x\" variables. So we now have a simple equation with one unknown.\r
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\n" ); document.write( "\n" ); document.write( "\"16%2B2y%2B2y=208\" Distribute\r
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\n" ); document.write( "\n" ); document.write( "\"4y%2B16=208\" Combine like terms on the left side\r
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\n" ); document.write( "\n" ); document.write( "\"4y=208-16\"Subtract 16 from both sides\r
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\n" ); document.write( "\n" ); document.write( "\"4y=192\" Combine like terms on the right side\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28192%29%2F%284%29\" Divide both sides by 4 to isolate y\r
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\n" ); document.write( "\n" ); document.write( "\"y=48\" Divide\r
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\n" ); document.write( "\n" ); document.write( "Now that we know that \"y=48\", we can plug this into \"x=8%2By\" to find \"x\"\r
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\n" ); document.write( "\n" ); document.write( "\"x=8%2B%2848%29\" Substitute \"48\" for each \"y\"\r
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\n" ); document.write( "\n" ); document.write( "\"x=56\" Simplify\r
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\n" ); document.write( "\n" ); document.write( "So our answer is \"x=56\" and \"y=48\"\r
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\n" ); document.write( "\n" ); document.write( "So the first car was going 56 mph and the second car was going 48 mph
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