document.write( "Question 984634: Mary, who is sixteen years old, is four times as old as her brother. How old will Mary be when she is twice as old as her brother? \n" ); document.write( "
Algebra.Com's Answer #605426 by macston(5194)\"\" \"About 
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\n" ); document.write( "M=Mary's age=16 yrs; B=brothers age; X=number of years until Mary is twice as old
\n" ); document.write( "M=4B
\n" ); document.write( "16 yrs=4B
\n" ); document.write( "4yrs=B Brother is 4 years old.
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\n" ); document.write( "M+X=2(B+X)
\n" ); document.write( "16yrs+X=2(4yrs+X)
\n" ); document.write( "16yrs+X=8yrs+2X
\n" ); document.write( "8yrs=X In 8 years Mary will be twice as old as brother.
\n" ); document.write( "M+8yrs=16yrs+8yrs=24yrs
\n" ); document.write( "ANSWER: Mary will be 24 years old when she is twice as old as her brother.
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\n" ); document.write( "CHECK:
\n" ); document.write( "16yrs+8yrs=2(4yrs+8yrs)
\n" ); document.write( "24yrs=2(12yrs)
\n" ); document.write( "24yrs=24yrs
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\n" ); document.write( "In 8 years, Mary will be 24 and brother will be 12.
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