document.write( "Question 136626: Alice leaves Denver, driving at a constant speed. After a while, she passes a mile marker displaying a two-digit number. One hour later, she passes a second marker with the same two digits in reverse order. In another hour she passes a third marker with the same two numbers separated by a zero. What is the rate of Alice's car in miles per hour? \n" ); document.write( "
Algebra.Com's Answer #100075 by ankor@dixie-net.com(22740)\"\" \"About 
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Alice leaves Denver, driving at a constant speed. After a while, she passes a mile marker displaying a two-digit number. One hour later, she passes a second marker with the same two digits in reverse order. In another hour she passes a third marker with the same two numbers separated by a zero. What is the rate of Alice's car in miles per hour?
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\n" ); document.write( "If we find the value of the mile markers we can find the speed easily.
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\n" ); document.write( "Let the 1st number be:
\n" ); document.write( "10x + y:
\n" ); document.write( "then
\n" ); document.write( "10y + x = the second number
\n" ); document.write( "and
\n" ); document.write( "100x + y = the third number
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\n" ); document.write( "We know:
\n" ); document.write( "3rd marker - 2nd marker = 2nd marker - 1st marker
\n" ); document.write( "(100x + y) - (10y + x) = (10y + x) - (10x + y)
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\n" ); document.write( "100x + y - 10y - x = 10y + x - 10x - y
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\n" ); document.write( "99x - 9y = 9y - 9x
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\n" ); document.write( "11x - y = y - x; simplified, divided by 9
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\n" ); document.write( "11x + x = y + y
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\n" ); document.write( "12x = 2y
\n" ); document.write( "or
\n" ); document.write( "6x = y
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\n" ); document.write( "In order for y to be a single digit, x = 1.
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\n" ); document.write( "1st mile marker = 16
\n" ); document.write( "2nd mile marker = 61
\n" ); document.write( "3rd mile marker = 106
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\n" ); document.write( "The difference between the markers is 45 miles, therefore her speed = 45 mph
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