document.write( "Question 514607: John is ten years older than Mary. Five years ago, John was double Mary's age. How old are they now? \n" ); document.write( "
Algebra.Com's Answer #343932 by Maths68(1474)\"\" \"About 
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Let
\n" ); document.write( "Present age of John = j
\n" ); document.write( "Present age of Mary = M\r
\n" ); document.write( "\n" ); document.write( "John is ten years older than Mary
\n" ); document.write( "j=m+10 .......(1)\r
\n" ); document.write( "\n" ); document.write( "Five years ago
\n" ); document.write( "j-5=m-5
\n" ); document.write( "then, John was double Mary's age
\n" ); document.write( "j-5=2(m-5)
\n" ); document.write( "j-5=2m-10
\n" ); document.write( "j=2m-10+5
\n" ); document.write( "j=2m-5
\n" ); document.write( "Put the value of j from (1) to above equation
\n" ); document.write( "m+10=2m-5
\n" ); document.write( "m-2m=-5-10
\n" ); document.write( "-m=-15
\n" ); document.write( "Multiply by (-1) both sides
\n" ); document.write( "(-1)-m=-15(-1)
\n" ); document.write( "m=15\r
\n" ); document.write( "\n" ); document.write( "Put the value of m in (1)\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "m=15\r
\n" ); document.write( "\n" ); document.write( "j=m+10 .......(1)
\n" ); document.write( "j=15+10
\n" ); document.write( "j=25\r
\n" ); document.write( "\n" ); document.write( "Present age of John = j = 25 years old
\n" ); document.write( "Present age of Mary = M = 15 years old
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