document.write( "Question 739567: 10 years before,dad's age was 3 times his son's age,10 years after,dad's age is double of son's age.what's son's age now? \n" ); document.write( "

Algebra.Com's Answer #451377 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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10 years before,dad's age was 3 times his son's age,
\n" ); document.write( "10 years after,dad's age is double of son's age.
\n" ); document.write( "what's son's age now?
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\n" ); document.write( "let d = dad's present age
\n" ); document.write( "let s = son's present age
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\n" ); document.write( "Write an equation for each statement.
\n" ); document.write( ":
\n" ); document.write( "\"10 years before, dad's age was 3 times his son's age,\"
\n" ); document.write( "d - 10 = 3(s-10)
\n" ); document.write( "d - 10 = 3s - 30
\n" ); document.write( "d = 3s - 30 + 10
\n" ); document.write( "d = 3s - 20
\n" ); document.write( ":
\n" ); document.write( "\"10 years after, dad's age is double of son's age.\"
\n" ); document.write( "d + 10 = 2(s+10)
\n" ); document.write( "d + 10 = 2s + 20
\n" ); document.write( "d = 2s + 20 - 10
\n" ); document.write( "d = 2s + 10
\n" ); document.write( ":
\n" ); document.write( "what's son's age now?
\n" ); document.write( "in the above equation, replace d with (3s-20)
\n" ); document.write( "3s - 20 = 2s + 10
\n" ); document.write( "3s - 2s = 10 + 20
\n" ); document.write( "s = 30 yrs old is the son's present age
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "You can find dad's age and check solutions in both statements
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