document.write( "Question 1076924: son 16 years younger than father.In 3 years sons age will 1\3 of his father.Find present age of sons \n" ); document.write( "
Algebra.Com's Answer #691501 by alanc(27)\"\" \"About 
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son 16 years younger than father.In 3 years sons age will 1\3 of his father.Find present age of sons
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\n" ); document.write( "We see there are 2 unknown values here.
\n" ); document.write( "Let s = the age of the son.
\n" ); document.write( "Let f = the age of the father.\r
\n" ); document.write( "\n" ); document.write( "The first sentence translates to : s = f - 16\r
\n" ); document.write( "\n" ); document.write( "The second sentence translates to (s + 3) = (1/3) * (f + 3)\r
\n" ); document.write( "\n" ); document.write( "We have 2 equations in 2 unknowns. We should be able to solve for s and f.\r
\n" ); document.write( "\n" ); document.write( "s = f - 16
\n" ); document.write( "(s + 3) = (1/3) * (f + 3)\r
\n" ); document.write( "\n" ); document.write( "s + 16 = f
\n" ); document.write( "3 ( s + 3) = f + 3\r
\n" ); document.write( "\n" ); document.write( "substitute for f.\r
\n" ); document.write( "\n" ); document.write( "3 (s + 3) = (s + 16) + 3
\n" ); document.write( "3s + 9 = s + 19
\n" ); document.write( "3s - s + 9 = 19
\n" ); document.write( "2s + 9 = 19
\n" ); document.write( "2s + 9 - 9 = 19 - 9
\n" ); document.write( "2s = 10
\n" ); document.write( "s = 10/2
\n" ); document.write( "s = 5\r
\n" ); document.write( "\n" ); document.write( "Therefore f = s + 16 = 5 + 16 = 21\r
\n" ); document.write( "\n" ); document.write( "The father is 21 years old and the son is 5 years old.\r
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