document.write( "Question 300711: father's age is three times the sum of ages of his two childen. after 5 year his will be twice the sum of ages of the son. find the present ages of father and son. \n" ); document.write( "
Algebra.Com's Answer #215760 by ankor@dixie-net.com(22740)\"\" \"About 
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father's age is three times the sum of ages of his two children.
\n" ); document.write( "after 5 years his will be twice the sum of the ages of the son.
\n" ); document.write( " find the present ages of father and son.
\n" ); document.write( ":
\n" ); document.write( "Let a = age of the son
\n" ); document.write( "Let b = age of the other child
\n" ); document.write( "Let f = fathers age
\n" ); document.write( ":
\n" ); document.write( "\"father's age is three times the sum of ages of his two children.\"
\n" ); document.write( "f = 3(a+b))
\n" ); document.write( "f = 3a + 3b
\n" ); document.write( ":
\n" ); document.write( "\"after 5 years his will be twice the sum of ages of the son. \"
\n" ); document.write( "f + 5 = 2(a + 5)
\n" ); document.write( "f + 5 = 2a + 10
\n" ); document.write( "f = 2a + 10 - 5
\n" ); document.write( "f = 2a + 5
\n" ); document.write( "replace f with (3a+3b)
\n" ); document.write( "3a + 3b = 2a + 5
\n" ); document.write( "3a - 2a = - 3b + 5
\n" ); document.write( "a = -3b + 5
\n" ); document.write( "Only one positive integer solution; b = 1, (other child's age)
\n" ); document.write( "a = -3(1) + 5
\n" ); document.write( "a = 2 yrs is the son's present age
\n" ); document.write( "then
\n" ); document.write( "f = 3(2+1)
\n" ); document.write( "f = 9 yrs is father's age, doesn't make sense, but if fits
\n" ); document.write( ":
\n" ); document.write( "check in the statement
\n" ); document.write( "\"after 5 year his will be twice the sum of ages of the son.\"
\n" ); document.write( "9 + 5 = 2(2+5)
\n" ); document.write( "14 = 2(7) \n" ); document.write( "
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