document.write( "Question 970972: Susan is 10 years old then her brother . In three years time,she will be twiced as old as her brother. What are their present ages? \n" ); document.write( "
Algebra.Com's Answer #593675 by ankor@dixie-net.com(22740)\"\" \"About 
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Susan is 10 years older than her brother.
\n" ); document.write( " In three years time, she will be twice as old as her brother.
\n" ); document.write( " What are their present ages?
\n" ); document.write( ":
\n" ); document.write( "let s = Susan's age
\n" ); document.write( "let b = brother's age
\n" ); document.write( ":
\n" ); document.write( "Write an equation for each statement
\n" ); document.write( "\" Susan is 10 years older than her brother\"
\n" ); document.write( "s = b + 10
\n" ); document.write( ":
\n" ); document.write( "In three years time, she will be twice as old as her brother.\"
\n" ); document.write( "s + 3 = 2(b + 3)
\n" ); document.write( "s + 3 = 2b + 6
\n" ); document.write( "s = 2b + 6 - 3
\n" ); document.write( "s = 2b + 3
\n" ); document.write( "replace s with (b+10) from the 1st statement.
\n" ); document.write( "b + 10 = 2b + 3
\n" ); document.write( "10 - 3 = 2b - b
\n" ); document.write( "7 = b
\n" ); document.write( "Brother is 7 yrs old
\n" ); document.write( "then
\n" ); document.write( "7 + 10 = 17 yrs is Susan's age
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Check these solutions in the statement
\n" ); document.write( "In three years time, she will be twice as old as her brother.\"
\n" ); document.write( "17 + 3 = 2(7 + 3)
\n" ); document.write( "20 = 2(10)\r
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