document.write( "Question 518918: a man is 4 times as old as his son.20 years later he will be just twice as old as his son.find their present ages. \n" ); document.write( "
Algebra.Com's Answer #345290 by Maths68(1474)\"\" \"About 
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Let
\n" ); document.write( "Present age of Man = m
\n" ); document.write( "Present age of Son = s\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Man is 4 times as old as his son.
\n" ); document.write( "m=4s.............(1)\r
\n" ); document.write( "\n" ); document.write( "20 years later
\n" ); document.write( "Man age = m+20
\n" ); document.write( "Son age = s+20\r
\n" ); document.write( "\n" ); document.write( "Then he will be just twice as old as his son.
\n" ); document.write( "m+20=2(s+20)
\n" ); document.write( "m+20=2s+40
\n" ); document.write( "m=2s+40-20
\n" ); document.write( "m=2s+20..............(2)\r
\n" ); document.write( "\n" ); document.write( "Put the value of m from (1) to (2)\r
\n" ); document.write( "\n" ); document.write( "4s=2s+20
\n" ); document.write( "4s-2s=20
\n" ); document.write( "2s=20
\n" ); document.write( "2s/2=20/2
\n" ); document.write( "s=10
\n" ); document.write( "Put the value of s in (1)
\n" ); document.write( "m=4s
\n" ); document.write( "m=4(10)
\n" ); document.write( "m=40\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Present age of Man = m = 40 years old
\n" ); document.write( "Present age of Son = s = 10 years old\r
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