document.write( "Question 311677: the mean age of a and b five years ago was 15 years . mean age og a,b and c today is 20 years . how old will c be after 10 years ?
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Algebra.Com's Answer #222924 by mananth(16946)\"\" \"About 
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the mean age of a and b five years ago was 15 years . mean age og a,b and c today is 20 years . how old will c be after 10 years ?
\n" ); document.write( "let the ages of a & b be x &y respectively.\r
\n" ); document.write( "\n" ); document.write( "x-5, y-5 will be their ages 5 years ago.
\n" ); document.write( "Their average = 15
\n" ); document.write( "x-5+y-5 /2 =15
\n" ); document.write( "x+y-10 / 2 = 15
\n" ); document.write( "x+y=30+10
\n" ); document.write( "x+y=40
\n" ); document.write( ".\r
\n" ); document.write( "\n" ); document.write( "Let the age of c be z years now
\n" ); document.write( "Their average is 20
\n" ); document.write( "x+y+z / 3 = 20
\n" ); document.write( "Plug the value of x+y\r
\n" ); document.write( "\n" ); document.write( "40+z = 60
\n" ); document.write( "z=20
\n" ); document.write( "z will be 20+10 = 30 years after 10 years.\r
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