document.write( "Question 1101089: Three years ago, Evan was one third of his sister's age. In a year's time, Evan's age doubled will match his sister's age. How old is Evan now? \n" ); document.write( "

Algebra.Com's Answer #715747 by ikleyn(52803) $\"\"$ $\"About$

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\n" ); document.write( "Three years ago, Evan was one third of his sister's age. In a year's time, Evan's age doubled will match his sister's age. How old is Evan now?
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document.write( "Let y be Evan's age, and\r\n" );
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document.write( "let x be the sister's age.\r\n" );
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document.write( "From the condition, you have these two equations\r\n" );
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document.write( "y - 3 = ,      (1)    (\"Three years ago, Evan was one third of his sister's age.\")\r\n" );
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document.write( "2*(y+1) = x + 1.      (2)     (\"In a year's time, Evan's age doubled will match his sister's age.\")\r\n" );
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document.write( "From eq(1),  3*(y-3) = x - 3  ====>  3y - 9 = x - 3  ====>  x = 3y - 6.\r\n" );
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document.write( "Now substitute it into eq(2). You will get\r\n" );
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document.write( "2*(y+1) = (3y-6) + 1  ====>  2y + 2 = 3y - 5  ====>  y = 2 + 5 = 7.\r\n" );
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document.write( "Answer.  Evan is 7 years old.  His sister is 15 years old (from eq(2)).\r\n" );
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\n" ); document.write( "\n" ); document.write( "The solution by @josgarithmetic (\"y = 10 Evan now\") is   W R O N G .\r
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\n" ); document.write( "There is a bunch of lessons on age word problems \r
\n" ); document.write( "\n" ); document.write( "    - Age problems and their solutions\r
\n" ); document.write( "\n" ); document.write( "    - A fresh formulation of a traditional age problem\r
\n" ); document.write( "\n" ); document.write( "    - Really intricate age word problem\r
\n" ); document.write( "\n" ); document.write( "    - Selected age word problems from the archive\r
\n" ); document.write( "\n" ); document.write( "    - Age problems for mental solution \r
\n" ); document.write( "\n" ); document.write( "in this site.\r
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\n" ); document.write( "\n" ); document.write( "Read them and become an expert in solving age problems.\r
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\n" ); document.write( "\n" ); document.write( "Also, you have this free of charge online textbook in ALGEBRA-I in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.\r
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\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this online textbook under the topic \"Age word problems\".\r
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\n" ); document.write( "\n" ); document.write( "Save the link to this online textbook together with its description\r
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\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-I
\n" ); document.write( "https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson\r
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\n" ); document.write( "\n" ); document.write( "to your archive and use it when it is needed.\r
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