document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1180854>Question 1180854</A>: <I><SPAN STYLE=\"word-break: break-all;\"> You need a 95% alcohol solution. On hand, you have a 15 mL of a 10% alcohol mixture. How much pure alcohol will you need to add to obtain the desired solution?\r<BR>\n" );
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document.write( "You will need<BR>\n" );
document.write( " (?) mL of pure alcohol<BR>\n" );
document.write( "to obtain<BR>\n" );
document.write( "(?) mL of the desired 95% solution. </SPAN>\n" );
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document.write( "Here is another very fast way to solve this kind of problem mentally....<br><BR>\n" );
document.write( "You are mixing 10% alcohol with 100% alcohol to get a mixture of 95% alcohol.<br><BR>\n" );
document.write( "95% is 85/90 = 17/18 of the way from 10% to 100%.  (Picture the three percentages 10, 95, and 100 on a number line, if it helps.  From 10 to 95 is a difference of 85; from 10 to 100 is a difference of 90; 85/90 = 17/18.)<br><BR>\n" );
document.write( "That means 17/18 of the mixture has to be the 100% alcohol, which means 1/18 of the mixture is the 15mL of 10% alcohol.<br><BR>\n" );
document.write( "So the amount of 100% alcohol is 17*15mL = 255mL.<br><BR>\n" );
document.write( "ANSWER: 255mL<br><BR>\n" );
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