<PRE><B>Question 515168</B>
Alyssa is a chemist with Gemco Pharmaceutical Company. She needs to prepare 12 ounces of a 9% hydrochloric acid solution. The only solutions she currently has available are 4% and 12% hydrochloric acid. How much should she use of each solution to obtain the needed solution? Use variables and representation if possible.
**
let x=ounces of 4% solution
12-x=ounces of 12% solution
..
4%x+12%(12-x)=9%*12
.04x+1.44-.12x=.09*12
-.08x=-.36
x=.36/.08
4=4.5 ounces
ans:
Alyssa should use of each of the following solutions to obtain the needed solution
4.5 ounces of 4% solution
and
7.5 ounces of 12% solution</PRE>