<PRE><B>Question 498788</B>
in the lab, robyn has two solutions that contain alcohol and is mixing them with each other. Soultion A is 6% alcohol and Solution Bis 20% alcohol. She uses 400 milliliters of Solution A. How many milliters of Solution B does she use, if the resulting mixture is a 12% alcohol solution?
**
let x=ml of 20% solution B used in resulting mixture.
400+x=ml of resulting 12% solution
..
6%(400)+20%x=12%(400+x)
.06*400+.2x=.12(400+x)
24+.2x=48+.12x
.08x=24
x=24/.08=300 ml
ans:
300 ml of 20% solution B used in resulting mixture.</PRE>