document.write( "Question 589674: Bottle A contains some water. Bottle B contains an equal amount of pure alcohol. First 1/3 of the water in A is poured into B. Stir Well. Then 1/3 of the mixture in B is poured into A. Stir Well. Again 1/3 of the mixture in A is poured into B. Stir Well. Finally the correct amount of mixture is poured from B into A so the both bottles contains the same amount of mixture. In what ratio is the pure alcohol divided between A and B now? \n" ); document.write( "
Algebra.Com's Answer #374938 by josmiceli(19441)\"\" \"About 
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Call the amount of water in A at the start \"+1+\" unit
\n" ); document.write( "Call the amount of alcohol in B at the start \"+1+\" unit
\n" ); document.write( "----------
\n" ); document.write( "After the 1st step,
\n" ); document.write( "A has \"+2%2F3+\" units of water in it
\n" ); document.write( "B has \"+1%2F3+\" units of water plus \"+1+\" unit of alcohol
\n" ); document.write( "----------
\n" ); document.write( "After the 2nd step,
\n" ); document.write( "\"+%281%2F3%29+%2A+%281%2F3%29+=+1%2F9+\" units of water from B is added to A, and
\n" ); document.write( "\"+%281%2F3%29%2A1+=+1%2F3+\" units of alcohol from B is added to A
\n" ); document.write( "Now A contains \"+2%2F3+%2B+1%2F9+=+7%2F9+\" units of water
\n" ); document.write( "and \"+1%2F3+\" units of alcohol
\n" ); document.write( "Now B contains \"+1%2F3+-+%281%2F3%29%2A%281%2F3%29+=+2%2F9+\" units of water
\n" ); document.write( "and \"+1+-+1%2F3+=+2%2F3+\" units of alcohol
\n" ); document.write( "---------
\n" ); document.write( "Note that after each step the total units of both water and alcohol must = 1
\n" ); document.write( "---------
\n" ); document.write( "After the next step:
\n" ); document.write( "\"+%281%2F3%29%2A%287%2F9%29+=+7%2F27+\" units of water from A is added to B
\n" ); document.write( "\"+%281%2F3%29%2A%281%2F3%29+=+1%2F9+\" units of alcohol from A is added to B
\n" ); document.write( "Now A contains \"+7%2F9+-+7%2F27+=+14%2F27+\" units of water
\n" ); document.write( "and \"+1%2F3+-+1%2F9+=+2%2F9+\" units of alcohol
\n" ); document.write( "Now B contains \"+2%2F9+%2B+7%2F27+=+13%2F27+\" units of water
\n" ); document.write( "and \"+2%2F3+%2B+1%2F9+=+7%2F9+\" units of alcohol
\n" ); document.write( "---------
\n" ); document.write( "check: water = \"+14%2F27+%2B+13%2F27+=+1+\" and
\n" ); document.write( "alcohol = \"+2%2F9+%2B+7%2F9+=+1+\"
\n" ); document.write( "OK
\n" ); document.write( "---------
\n" ); document.write( "After the next step:
\n" ); document.write( "Some fraction of the mixture in B is poured into A
\n" ); document.write( "Let that fraction = \"+1%2Fx+\"
\n" ); document.write( "Now B contains \"+13%2F27+-+13%2F%2827x%29+=+%2813%2F27%29%2A%28+1+-+1%2Fx+%29+\" units of water
\n" ); document.write( "and \"+7%2F9+-+7%2F%289x%29+=+%287%2F9%29%2A%28+1++-+1%2Fx%29+\" units of alcohol
\n" ); document.write( "Now A contains \"+14%2F27+%2B+%281%2Fx%29%2A%2813%2F27%29++\" units of water
\n" ); document.write( "and \"+2%2F9+%2B+%281%2Fx%29%2A%287%2F9%29+\" units of alcohol
\n" ); document.write( "----------
\n" ); document.write( "The mixture in A now = the mixture in B, so
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\"+-42%2F%2827x%29+=+-14%2F27+\"
\n" ); document.write( "\"+21%2F%2827x%29+=+7%2F27+\"
\n" ); document.write( "\"+21%2Fx+=+7+\"
\n" ); document.write( "\"+x+=+3+\"
\n" ); document.write( "----------
\n" ); document.write( "The units of alcohol in A is now
\n" ); document.write( "\"+2%2F9+%2B+%281%2F3%29%2A%287%2F9%29+=+6%2F27+%2B+7%2F27+\"
\n" ); document.write( "\"+6+%2F27+%2B+7%2F27+=+13%2F27+\"
\n" ); document.write( "The units of alcohol in B is now
\n" ); document.write( "\"+%287%2F9%29%2A%28+1+-+1%2F3+%29+=+%287%2F9%29%2A%282%2F3%29+\"
\n" ); document.write( "\"+%287%2F9%29%2A%282%2F3%29+=+14%2F27+\"
\n" ); document.write( "The ratio of alcohol is
\n" ); document.write( "A/B = 13/14
\n" ); document.write( "----------
\n" ); document.write( "Unless I goofed somewhere
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