document.write( "Question 519251: A man is 3 times as old as his son. 8 years ago the product of their age was 112. Find their ages \n" ); document.write( "
Algebra.Com's Answer #345468 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( "A man is 3 times as old as his son.
\n" ); document.write( "m=3s.......(1)
\n" ); document.write( "8 years ago,
\n" ); document.write( "Man age = m-8
\n" ); document.write( "Song age = s-8
\n" ); document.write( "Then, the product of their age was 112.
\n" ); document.write( "(m-8)(s-8)=112
\n" ); document.write( "ms-m8-8s+64=112
\n" ); document.write( "ms-m8-8s=112-64
\n" ); document.write( "ms-m8-8s=48..............(2)
\n" ); document.write( "Substitute the value from (1) to (2)
\n" ); document.write( "(3s)s-(3s)8-8s=48
\n" ); document.write( "3s^2-24s-8s=48
\n" ); document.write( "3s^2-32s=48
\n" ); document.write( "3s^2-32s-48=0
\n" ); document.write( "3s^2-36s+4s-48=0
\n" ); document.write( "3s(s-12)+4(s-12)=0
\n" ); document.write( "(s-12)(3s+4)=0
\n" ); document.write( "s-12=0 or 3s+4=0
\n" ); document.write( "s=12 or s=-4/3 (inadmissable)
\n" ); document.write( "so
\n" ); document.write( "s=12
\n" ); document.write( "Put the value of s in (1)
\n" ); document.write( "m=3s
\n" ); document.write( "m=3(12)
\n" ); document.write( "m=36\r
\n" ); document.write( "\n" ); document.write( "Present age of Man = m = 36 years old
\n" ); document.write( "Present age of Son = s = 12 years old
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