document.write( "Question 1011390: 10 years ago, Mona's mother was 4 times older than her daughter. After 10 years, the mother will be twice older than the daughter. Mona's present age is: \n" ); document.write( "

Algebra.Com's Answer #627034 by ikleyn(52786) $\"\"$ $\"About$

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\n" ); document.write( "10 years ago, Mona's mother was 4 times older than her daughter.
\n" ); document.write( "After 10 years, the mother will be twice older than the daughter. Mona's present age is:
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document.write( "Let x be the Mona's present age, and let y be the Mona's mother present age.\r\n" );
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document.write( "Ten years ago, Mona's age was x-10, and her mother's age was y-10.\r\n" );
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document.write( "Since ten years ago Mona's mother was 4 times older than her daughter, you have an equation\r\n" );
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document.write( "y-10 = 4*(x-10).\r\n" );
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document.write( "After 10 years, the mother's age will be y+10, and Mona's age will be x+10.\r\n" );
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document.write( "Since after 10 years, the mother will be twice older than the daughter, it gives you the second equation\r\n" );
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document.write( "y + 10 = 2*(x+10)\r\n" );
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document.write( "Solve this system for x and y:\r\n" );
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document.write( "Answer. x = 20. Mona's present age is 20 years.\r\n" );
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