document.write( "Question 1203535: You need to strengthen a 22% alcohol solution with a pure alcohol solution to obtain a 70% solution. How much pure alcohol should you add to 100 milliliters of the 22% solution? \n" ); document.write( "
Algebra.Com's Answer #839176 by greenestamps(13200)![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "The standard algebraic solution looks something like this: \n" ); document.write( "100 ml of 22% alcohol, plus x ml of 100% alcohol, yields (100+x) ml of 70% alcohol. \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "ANSWER: 160 ml \n" ); document.write( "Here is an alternative, informal method which often makes reaching the answer easier. \n" ); document.write( "Picture a number line showing the three percentages -- 22, 70, and 100. Calculate that 70 is 48/78 of the way from 22 to 100 (22 to 70 is a difference of 48; 22 to 100 is a difference of 78). \n" ); document.write( "That fraction 48/78 means the two ingredients must be mixed in the ratio 48:(78-48) = 48:30 = 8:5. Since 70% is closer to 100% than to 22%, the larger portion must be the 100% alcohol. Then we have the proportion \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "And again of course the answer is 160 ml. \n" ); document.write( " \n" ); document.write( " |