document.write( "Question 972574: Jacky is tWo-third as old as her sister.Twenty years from now, she will be seven-eighths as old as her sister.How old is jacky? \n" ); document.write( "
Algebra.Com's Answer #594887 by macston(5194)\"\" \"About 
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\n" ); document.write( "S=sister's age; J=Jacky's age=(2/3)S
\n" ); document.write( "J+20=(7/8)(S+20) Substitute for J
\n" ); document.write( "(2/3)S+20=(7/8)S+(140/8)
\n" ); document.write( "20-(140/8)=(7/8)S-(2/3)S
\n" ); document.write( "(160/8)-(140/8)=(21/24)S-(16/24)S
\n" ); document.write( "(20/8)=(5/24)S
\n" ); document.write( "60/24=5S/24
\n" ); document.write( "60=5S
\n" ); document.write( "12=S Sister's age is 12.
\n" ); document.write( "J=(2/3)S=(2/3)12=8
\n" ); document.write( "ANSWER: Jacky's age is 8.
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\n" ); document.write( "CHECK:
\n" ); document.write( "J+20=(7/8)(S+20)
\n" ); document.write( "8+20=(7/8)(12+20)
\n" ); document.write( "28=(7/8)(32)
\n" ); document.write( "28=28
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