SOLUTION: Dr. Alvarado is a chemist. She needs to mix 10 liters of a solution of a certain chemical that is 64% pure. (That is, 64% is the chemical, and the rest is water.) To do this, she w

Algebra ->  Customizable Word Problem Solvers  -> Mixtures -> SOLUTION: Dr. Alvarado is a chemist. She needs to mix 10 liters of a solution of a certain chemical that is 64% pure. (That is, 64% is the chemical, and the rest is water.) To do this, she w      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 1064823: Dr. Alvarado is a chemist. She needs to mix 10 liters of a solution of a certain chemical that is 64% pure. (That is, 64% is the chemical, and the rest is water.) To do this, she will mix a solution that is 70% pure with one that is 50% pure. How many liters of each should she use?
Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
let x be the number of liters of the 70% solution
let y be the number of liters of the 50% solution
:
1) x + y = 10
:
2) 0.70x + 0.50y = 0.64 * 10 = 6.4
:
solve equation 1 for x
:
x = 10 - y
:
substitute for x in equation 2
:
0.70 * (10 - y) + 0.50y = 6.4
:
7 - 0.70y + 0.50y = 6.4
:
-0.20y = -0.60
:
y = 3
x = 7
:
************************************************
Dr. Alvarado mixes 7 liters of the 70% pure and
3 liters of the 50% pure
************************************************
: