document.write( "Question 608055: How many cups of grapefruit juice must be added to 20 cups of a punch that is 10% grapefruit juice to obtain a punch that is 25% grapefruit juice? You will impress me extra, if you include your work. Hint: you do not end with twenty cups of punch. \n" ); document.write( "

Algebra.Com's Answer #383058 by josmiceli(19441) $\"\"$ $\"About$

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\n" ); document.write( "Let $\"+x+\"$ = cups of grapefruit juice that needs to be added
\n" ); document.write( " $\"+.1%2A20+=+2+\"$ = cups of grapefruit juice in 20 cups of 10% punch
\n" ); document.write( "( the part that isn't grapefruit juice might be water, but that
\n" ); document.write( "doesn't really matter )
\n" ); document.write( "----------------
\n" ); document.write( " $\"+%28+x+%2B+2+%29+%2F+%28+x+%2B+20+%29+=+.25+\"$
\n" ); document.write( " $\"+x+%2B+2+=+.25%2A%28+x+%2B+20+%29+\"$
\n" ); document.write( " $\"+x+%2B+2+=+.25x+%2B+5+\"$
\n" ); document.write( " $\"+.75x+=+3+\"$
\n" ); document.write( " $\"+x+=+4+\"$
\n" ); document.write( "You must add 4 cups of grapefruit juice
\n" ); document.write( "check:
\n" ); document.write( " $\"+%28+4+%2B+2+%29+%2F+%28+4+%2B+20+%29+=+.25+\"$
\n" ); document.write( " $\"+6%2F24+=+.25+\"$
\n" ); document.write( " $\"+6+=+.25%2A24+\"$
\n" ); document.write( " $\"+6+=+6+\"$
\n" ); document.write( "OK \n" ); document.write( "

\n" );