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You can put this solution on YOUR website!
at present,the sum of the ages of a father and his son is 43 years.
\n" ); document.write( "f + s = 43
\n" ); document.write( "or
\n" ); document.write( "f = (43-s)
\n" ); document.write( ":
\n" ); document.write( "we have three unknowns and only two equations here, but full steam ahead!
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\n" ); document.write( "In n years,n>0, the father will be four times the son age.
\n" ); document.write( "f + n = 4(s + n)
\n" ); document.write( "f + n = 4s + 4n
\n" ); document.write( "f = 4s + 4n - n
\n" ); document.write( "f = 4s + 3n
\n" ); document.write( "Replace f with (43-s)
\n" ); document.write( "43 - s = 4s + 3n
\n" ); document.write( "43 = 4s + s + 3n
\n" ); document.write( "43 = 5s + 3n
\n" ); document.write( "rearrange this
\n" ); document.write( "-5s = 3n - 43
\n" ); document.write( "mult by -1
\n" ); document.write( "5s = -3n + 43
\n" ); document.write( "Here is a break, since we are dealing with integers, we can say
\n" ); document.write( "\"What value for n would make the value on the right a multiple of 5?\"
\n" ); document.write( "How about n = 1
\n" ); document.write( "5s = -3(1) + 43
\n" ); document.write( "5s = 40
\n" ); document.write( "s = 40/5
\n" ); document.write( "s = 8 yrs old is the son's age
\n" ); document.write( "then Dad is 35 yrs old, right
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\n" ); document.write( "In 1 yr, s=9: f=36, Dad is 4 times as old as sonny
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\n" ); document.write( "But that is not the only solution, why don't you check it out when n = 6?
\n" ); document.write( ":
\n" ); document.write( "And how about when n=11?
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