document.write( "Question 738312: 12. The sum of numerator and denominator of a fraction is 8. I 3 is added to both numerator and denominator, the fraction becomes ¾. Find the fraction. \n" ); document.write( "
Algebra.Com's Answer #450808 by KMST(5328)\"\" \"About 
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THE FIFTH-GRADER WAY:
\n" ); document.write( "after adding 3 to numerator and denominator the new fraction is
\n" ); document.write( "\"3%2F4=6%2F8=9%2F12=12%2F16=15%2F20\"= .....
\n" ); document.write( "If the new fraction was \"3%2F4\", the original fraction would have been \"0%2F1\". That is just zero, which is not much of a fraction, and even if you say that the numerator is \"0\" and the denominator is \"1\", the sum of numerator plus denominator would be \"0%2B1=1\", which is not \"8\".
\n" ); document.write( "If the new fraction was \"6%2F8\", the original fraction would have been \"%286-3%29%2F%288-3%29=3%2F5\", and that is a solution to the problem, because \"3%2B5=8\".
\n" ); document.write( "since the wording suggests that there is one solution, no need to try \"9%2F12\", \"12%2F16\", etc, but it is clear that those would make an original fraction with a sum of numerator plus denominator greater than \"8\".
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\n" ); document.write( "THE ALGEBRA WAY:
\n" ); document.write( "\"x%2Fy\"= the fraction
\n" ); document.write( "\"x\"= the numerator
\n" ); document.write( "\"y\"= the denominator
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\n" ); document.write( "The sum of numerator and denominator of a fraction is 8 translates into
\n" ); document.write( "\"x%2By=8\"
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\n" ); document.write( "If 3 is added to both numerator and denominator, the fraction becomes \"3%2F4\" translates into
\n" ); document.write( "\"%28x%2B3%29%2F%28y%2B3%29=3%2F4%7D%7D+--%3E+%7B%7B%7B4%2A%28x%2B3%29=3%2A%28y%2B3%29\" --> \"4x%2B12=3y%2B9\" --> \"4x-3y=9-12\" --> \"4x-3y=-3\"
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\n" ); document.write( "Now we have to solve the system \"system%28x%2By=8%2C4x-3y=-3%29\"
\n" ); document.write( "We solve it any way we can to find \"highlight%28x=3%29\" and \"highlight%28y=5%29\"
\n" ); document.write( "SUBSTITUTION:
\n" ); document.write( "\"x%2By=8\"-->\"x=8-y\"
\n" ); document.write( "\"system%28x=8-y%2C4x-3y=-3%29\" --> \"4%2A%288-y%29-3y=-3\" -->
\n" ); document.write( "\"32-4y-3y=-3\" --> \"32-7y=-3\" --> \"32%2B3=7y\" --> \"7y=35\" -->\"y=35%2F7\" --> \"highlight%28y=5%29\"
\n" ); document.write( "Then \"system%28y=5%2Cx=8-y%29\" --> \"x=8-5\" --> \"highlight%28x=3%29\"
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