document.write( "Question 1180714: A father is 3 times older than his son.
\n" ); document.write( "Both their ages add up to 54.
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Algebra.Com's Answer #810445 by MathLover1(20850) $\"\"$ $\"About$

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let father's age be $\"f\"$ and son's age $\"s\"$ \r
\n" ); document.write( "\n" ); document.write( "if a father is $\"3\"$ times older than his son, we have\r
\n" ); document.write( "\n" ); document.write( " $\"f=3s\"$ ....eq.1\r
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\n" ); document.write( "\n" ); document.write( "if both their ages add up to $\"54\"$ , we have\r
\n" ); document.write( "\n" ); document.write( " $\"f%2Bs=54\"$ ....eq.2\r
\n" ); document.write( "\n" ); document.write( "substitute $\"f\"$ from eq.1\r
\n" ); document.write( "\n" ); document.write( " $\"3s%2Bs=54\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"4s=54\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"s=13.5\"$ or $\"13\"$ and $\"1%2F2\"$ \r
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\n" ); document.write( "\n" ); document.write( "then $\"f=3%2A13.5\"$ => $\"f=40.5\"$ or $\"40\"$ and $\"1%2F2\"$ \r
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\n" ); document.write( "\n" ); document.write( " their ages are:\r
\n" ); document.write( "\n" ); document.write( "father is $\"40\"$ and $\"1%2F2\"$ years old
\n" ); document.write( "son is $\"13\"$ and $\"1%2F2\"$ years old\r
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