document.write( "Question 1170858: Mary is twice as old as Jane was when Mary was as old as Jane is now. In 3 years Mary will be 3 times as old as Jane was 4 years ago. Find their present ages. \n" ); document.write( "
Algebra.Com's Answer #795780 by ankor@dixie-net.com(22740)\"\" \"About 
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Mary is twice as old as Jane was when Mary was as old as Jane is now.
\n" ); document.write( "let m-j = d, the difference in their ages
\n" ); document.write( "m = 2(j - d)
\n" ); document.write( "m = 2j - 2d
\n" ); document.write( "replace d with m-j
\n" ); document.write( "m = 2j - 2(m-j)
\n" ); document.write( "m = 2j - 2m + 2j
\n" ); document.write( "m = 4j - 2m
\n" ); document.write( "m + 2m = 4j
\n" ); document.write( "3m = 4j
\n" ); document.write( ":
\n" ); document.write( "In 3 years Mary will be 3 times as old as Jane was 4 years ago.
\n" ); document.write( "m + 3 = 3(j-4)
\n" ); document.write( "m + 3 = 3j - 12
\n" ); document.write( "m = 3j - 12 - 3
\n" ); document.write( "m = 3j - 15
\n" ); document.write( ":
\n" ); document.write( "in the first equation, replace m with (3j-15)
\n" ); document.write( "3(3j - 15) = 4j
\n" ); document.write( "9j - 45 = 4j
\n" ); document.write( "9j - 4j = 45
\n" ); document.write( "5j = 45
\n" ); document.write( "j = 45/5
\n" ); document.write( "j = 9 yrs is Jane's age
\n" ); document.write( "then
\n" ); document.write( "m = 3j - 15
\n" ); document.write( "m = 3(9) - 15
\n" ); document.write( "m = 12 yrs is Mary's age\r
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