document.write( "Question 165862: John is 4 years older than his sister and 6 years ago he was twice his sister's age then. How old is each now? \n" ); document.write( "

Algebra.Com's Answer #122341 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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Let j = John's age now
\n" ); document.write( "let s = sister's age now
\n" ); document.write( ":
\n" ); document.write( "Write an equation for each statement:
\n" ); document.write( ":
\n" ); document.write( "\"John is 4 years older than his sister\"
\n" ); document.write( "j = s + 4
\n" ); document.write( ":
\n" ); document.write( "\"6 years ago he was twice his sister's age then.\"
\n" ); document.write( "(j-6) = 2(s-6)
\n" ); document.write( "j - 6 = 2s - 12
\n" ); document.write( "j = 2s - 12 + 6
\n" ); document.write( "j = 2s - 6
\n" ); document.write( ":
\n" ); document.write( " How old is each now?
\n" ); document.write( ":
\n" ); document.write( "From the 1st equation, substitute (s+4) for j in the last equation
\n" ); document.write( "s + 4 = 2s - 6
\n" ); document.write( "4 + 6 = 2s - s
\n" ); document.write( "10 = s (sister's age now)
\n" ); document.write( "then
\n" ); document.write( "10 + 4 = 14 yr John's age now
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Check solution in the statement:
\n" ); document.write( "\"6 years ago he was twice his sister's age then.\"
\n" ); document.write( "14 - 6 = 2(10 - 6) \n" ); document.write( "

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