document.write( "Question 1077694: average age of a boy and a girl is 14 yrs. The average age of the same boy, the girl and her twin sister is 16 yrs. What is the boy's age? \n" ); document.write( "
Algebra.Com's Answer #692164 by amfagge92(93)\"\" \"About 
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let their ages be a , b and 2b
\n" ); document.write( "a+b/2=14....i
\n" ); document.write( "a+2b/3=16..ii
\n" ); document.write( "solving we have
\n" ); document.write( "a+b=28....iii
\n" ); document.write( "a+2b=48...iv
\n" ); document.write( "a=28-b......v
\n" ); document.write( "subtitute a in eqn iv
\n" ); document.write( "28-b+2b=48
\n" ); document.write( "b=20
\n" ); document.write( "subtitute b in enq v
\n" ); document.write( "a=28-20
\n" ); document.write( "a=8.
\n" ); document.write( "the boy's age is 8.
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