document.write( "Question 404890: Mary is six years older than Jean. The sum of their ages is 20. How old is Mary \n" ); document.write( "
Algebra.Com's Answer #286119 by keksjr(7)\"\" \"About 
You can put this solution on YOUR website!
Let Mary's age be: x , and Let Jean's age be y:\r
\n" ); document.write( "\n" ); document.write( "Since Mary is 6yrs older than Jean, therefore it implies that:\r
\n" ); document.write( "\n" ); document.write( "Mary's age = Jean's age + 6; x=y+6\r
\n" ); document.write( "\n" ); document.write( "And the sum of their ages being 20, that also implies that:\r
\n" ); document.write( "\n" ); document.write( "Mary's age + Jean's age = 20; x+y=20\r
\n" ); document.write( "\n" ); document.write( "Therefore lets find \"y\" that is Jean's age by substituting x=y+6 into x+y=20;\r
\n" ); document.write( "\n" ); document.write( " y+6+y=20
\n" ); document.write( " 2y =20-6
\n" ); document.write( " 2y =14
\n" ); document.write( "By Dividing through by 2; y =7\r
\n" ); document.write( "\n" ); document.write( "Then in finding how old Mary is: x=y+6
\n" ); document.write( " x=7+6
\n" ); document.write( " x=13\r
\n" ); document.write( "\n" ); document.write( "Therefore, Mary is 13yrs old
\n" ); document.write( " \n" ); document.write( "
\n" );