document.write( "Question 1206003: A brother is 3 years older than his sister, five years ago, the ratio of their ages were 4:3 find their present ages \n" ); document.write( "

Algebra.Com's Answer #843159 by ikleyn(52803) $\"\"$ $\"About$

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\n" ); document.write( "A brother is 3 years older than his sister, five years ago, the ratio of their ages $\"highlight%28cross%28were%29%29\"$ was 4:3.
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document.write( "Let b be the brother's age 5 years ago.\r\n" );
document.write( "Then the sister's age at that time was (b-3) years.\r\n" );
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document.write( "From the problem, we have this proportion\r\n" );
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document.write( "     = .\r\n" );
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document.write( "Cross multiply and find \"b\"\r\n" );
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document.write( "    3b = 4*(b-3)\r\n" );
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document.write( "    3b = 4b - 12\r\n" );
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document.write( "    12 = 4b - 3b\r\n" );
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document.write( "    12 =   b\r\n" );
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document.write( "     b = 12.\r\n" );
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document.write( "5 years ago the brother was 12 years old; the sister was 12-3 = 9 years old.\r\n" );
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document.write( "Hence, now the brother is 12+5 = 17 years old; the sister is 9+5 = 14 years old.    ANSWER\r\n" );
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