document.write( "Question 126838: Mary is twice as old as Rachel will be in seven years. Four years ago, Mary was four times as old as Rachel. How old is Mary now? \n" ); document.write( "
Algebra.Com's Answer #93136 by ankor@dixie-net.com(22740)\"\" \"About 
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Let M = Mary's age now
\n" ); document.write( "Let R = Rachel's age now
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\n" ); document.write( "Write an equation for each statement:
\n" ); document.write( ":
\n" ); document.write( "Mary is twice as old as Rachel will be in seven years.
\n" ); document.write( "M = 2(R+7)
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\n" ); document.write( "Four years ago they would be:
\n" ); document.write( "(M-4)
\n" ); document.write( "(R-4)
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\n" ); document.write( "Four years ago, Mary was four times as old as Rachel.
\n" ); document.write( "(M-4) = 4(R-4); just do some basic algebra here
\n" ); document.write( "M - 4 = 4R - 16
\n" ); document.write( "M = 4R - 16 + 4
\n" ); document.write( "M = 4R - 12
\n" ); document.write( "Substitute 2(R+7) for M, find R
\n" ); document.write( "2(R+7) = 4R - 12
\n" ); document.write( "2R + 14 = 4R - 12
\n" ); document.write( "2R - 4R = -12 - 14
\n" ); document.write( "-2R = -26
\n" ); document.write( "R = \"%28-26%29%2F%28-2%29\"
\n" ); document.write( "R = + 13 yrs is Rachel's age now
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\n" ); document.write( "How old is Mary now?
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\n" ); document.write( "We know that M = 2(R+7); substitute 13 for R
\n" ); document.write( "M = 2(13+7)
\n" ); document.write( "M = 2(20)
\n" ); document.write( "M = 40 yrs is Mary's age now
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\n" ); document.write( "Check solutions in the statement:
\n" ); document.write( "\"Four years ago, Mary was four times as old as Rachel.\"
\n" ); document.write( "(40-4) = 4(13 - 4)
\n" ); document.write( "36 = 4(9); confirms our solution
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\n" ); document.write( "Did this make sense to you? This is a good method to do all these kind of problems;
\n" ); document.write( "First thing, write an equation for each statement. Let the basic operations of
\n" ); document.write( " algebra carry you thru. Let me know what you think. \n" ); document.write( "
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