document.write( "Question 312095: In five years, Sylvia will be twice as old as Luke. Thirteen years ago, Sylvia was three times as old as Luke. How many years ago was Sylvia four times as old as Luke?\r
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Algebra.Com's Answer #223225 by ankor@dixie-net.com(22740)\"\" \"About 
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In five years, Sylvia will be twice as old as Luke.
\n" ); document.write( "S + 5 = 2(L + 5)
\n" ); document.write( "S + 5 = 2L + 10
\n" ); document.write( "S = 2L + 10 - 5
\n" ); document.write( "S = 2L + 5
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\n" ); document.write( " Thirteen years ago, Sylvia was three times as old as Luke.
\n" ); document.write( "S - 13 = 3(L - 13)
\n" ); document.write( "S - 13 = 3L - 39
\n" ); document.write( "S = 3L - 39 + 13
\n" ); document.write( "S = 3L - 26
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\n" ); document.write( "Find L's age
\n" ); document.write( "3L - 26 = 2L + 5
\n" ); document.write( "3L - 2L = 5 + 26
\n" ); document.write( "L = 31 yrs
\n" ); document.write( "Find S
\n" ); document.write( "S = 2(31) + 5
\n" ); document.write( "S = 67 yrs
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\n" ); document.write( "How many years ago was Sylvia four times as old as Luke?
\n" ); document.write( "Let t = no. of years for this to be true
\n" ); document.write( "S - t = 4(L - t)
\n" ); document.write( "67 - t = 4(31 - t)
\n" ); document.write( "67 - t = 124 - 4t
\n" ); document.write( "4t - t = 124 - 67
\n" ); document.write( "3t = 57
\n" ); document.write( "t = \"57%2F3\"
\n" ); document.write( "t = 19 yrs ago
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