Roman mixes 12 liters of 8% acid solution with a 20% acid solution, which results in a 16% acid solution. Find the number of liters of 20% acid solution in the new mixture. Construct a table to organize the information, and show all of your work to solve the problem.

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jpes2193 · Answer

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jpes2193 · Answer

make a chart with 3 column headers 
number of ltrs * concentration = Amount of pure acid solution
 then in the first column your 8% sol will be x and your 20% sol will be y and the total for that will be 12
the second column (concentration) will be .08 then .20  and the total will be .16 
in the last column write what the top row is across ( you should get .08x) because we stated that the number of liters times the concentration = amount of pure solution. do this for the second row. 
finally  create a system of equations 
.08x + .20y = (.15)(12) 
x + y= 12 
solve with substitution.

tishockjo · Answer

thank you so much. I really appreciated your help ^^

jpes2193 · Answer

no problem.. you can also use this same set up for mixture of dry substances (like coffee or trail mix), problems involving interest and so on... i like the chart because you can see where each problem comes from.