document.write( "Question 619534: Byron is 3 years older than doug. The product of their age is 40, how old is Doug? \n" ); document.write( "

Algebra.Com's Answer #390080 by Maths68(1474) $\"\"$ $\"About$

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Let
\n" ); document.write( "Present age of Byron = b
\n" ); document.write( "Present age of Doug = d\r
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\n" ); document.write( "\n" ); document.write( "Byron is 3 years older than Doug
\n" ); document.write( "b=d+3.........(1)
\n" ); document.write( "The product of their age is 40
\n" ); document.write( "bd=40...........(2)
\n" ); document.write( "Substitute the value of b from (1) to (2)
\n" ); document.write( "(d+3)d=40
\n" ); document.write( "d^2+3d=40
\n" ); document.write( "d^2+3d-40=0
\n" ); document.write( "Now solve for d
\n" ); document.write( "d^2+8d-5d-40=0
\n" ); document.write( "d(d+8)-5(d+8)=0
\n" ); document.write( "(d-5)(d+8)=0
\n" ); document.write( "d-5=0 or d+8=0
\n" ); document.write( "d=5 or d=-8
\n" ); document.write( "d=-8 (inadmissible)
\n" ); document.write( "So d=5
\n" ); document.write( "Put the value of d in (1)
\n" ); document.write( "b=d+3.........(1)
\n" ); document.write( "b=5+3
\n" ); document.write( "b=8\r
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\n" ); document.write( "\n" ); document.write( "Present age of Byron = b = 8 years old
\n" ); document.write( "Present age of Doug = d = 5 years old \n" ); document.write( "

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