document.write( "Question 209326: Please help me with the following word problem, I can not do percentages at all and I can not figure out the answer. Thank you so much! A chemist wants to mix a 5% alcohol solution with a 25% alcohol solution to obtain 8 liters of a 20% alcohol solution. How much (in liters) of the 25% solution should she use? \n" ); document.write( "
Algebra.Com's Answer #158244 by josmiceli(19441)![]() ![]() You can put this solution on YOUR website! What might help you is to always \n" ); document.write( "remember that percent means \n" ); document.write( "\"per one-hundred\", so whenever \n" ); document.write( "you see %, you must divide by \n" ); document.write( "100. \n" ); document.write( "------------------------------ \n" ); document.write( "A good question to ask with this \n" ); document.write( "problem is: \"How much water and \n" ); document.write( "how much alcohol end up in the \n" ); document.write( "final solution? \n" ); document.write( "------------------------------ \n" ); document.write( "Let \n" ); document.write( "Let \n" ); document.write( "------------------------------ \n" ); document.write( "The equation to solve in words is: \n" ); document.write( "(alcohol in 5% solution)+(alcohol in 25% soltion)/(alcohol + water in 20% solution) = 20% \n" ); document.write( "So, I can write: \n" ); document.write( "(1) \n" ); document.write( "(2) \n" ); document.write( "Multiply both sides of (1) by \n" ); document.write( "(1) \n" ); document.write( "(1) \n" ); document.write( "Multiply both sides of (2) by \n" ); document.write( "(2) \n" ); document.write( "(2) \n" ); document.write( "And, subtracting: \n" ); document.write( "(1) \n" ); document.write( "(2) \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "She should use 6 liters of the 25% solution \n" ); document.write( "check answer: \n" ); document.write( "(2) \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "Go back to (1) \n" ); document.write( "(1) \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "It always helps if you can sum up the problem in \n" ); document.write( "an equation with words like I did (It helps me a lot)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |