<PRE><B>Question 150851</B>
If beaker A contains a 15% solution of sulfuric acid and beaker B contains a 20% solution of sulfuric acid, how much from each beaker should be used to make 6 liters of a 18% solution of sulfuric acid? 
----------------------
EQUATIONS:
Quantity Equation: a + b = 6 L
Active Ingrediant: 0.15a + 0.20b = 0.18(6) = 1.08
----------------
Rearrange for elimination:
15a + 15b = 90
15a + 20b = 108
------------------
Subtract 1st from 2nd to get:
5b = 18
b = 3.6 L (amt. of 15% solution in the mix)
Since a+b=6, a = 6-3.6 = 2.4 L (amt. of 20% solution in the mix)
======================================
Cheers,
Stan H.</PRE>