document.write( "Question 505938: father’s age is three times the sum of the ages of his two children, but 20 years hence his age will be equal to the sum of their ages. Then the father’s ageis: \n" ); document.write( "
Algebra.Com's Answer #340048 by josmiceli(19441)\"\" \"About 
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Let \"f\" = father's age
\n" ); document.write( "Let \"s\" = the sum of his children's ages
\n" ); document.write( "given:
\n" ); document.write( "(1) \"+f+=+3s+\"
\n" ); document.write( "\"+f+%2B+20+=+s+%2B+40+\" (add 20 years for each child)
\n" ); document.write( "(2) \"+f+-+s+=+20+\"
\n" ); document.write( "substitute (1) into (2)
\n" ); document.write( "(2) \"+3s+-+s+=+20+\"
\n" ); document.write( "(2) \"+2s+=+20+\"
\n" ); document.write( "(2) \"+s+=+10+\"
\n" ); document.write( "and
\n" ); document.write( "(1) \"+f+=+3s+\"
\n" ); document.write( "(1) \"+f+=+30+\"
\n" ); document.write( "The father is 30\r
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