In the lab, Susan has two solutions that contain alcohol and is mixing them with each other. Solution A is 12% alcohol and Solution B is 40% alcohol. She uses 200 milliliters of Solution A. How many milliliters of Solution B does she use, if the resulting mixture is a 32% alcohol solution?

Question

In the lab, Susan has two solutions that contain alcohol and is mixing them with each other. Solution A is 12%  alcohol and Solution B is 40%  alcohol. She uses 200 milliliters of Solution A. How many milliliters of Solution B does she use, if the resulting mixture is a  32% alcohol solution?

anonymous · Answer

Off the the top of my head...


(% A)(mL A) + (% B)(mL B) = (% mixture)(mL mixture)

(12% solute)(200mL) + (40% solute)(v mL) = (32% solute)((200+v) mL)

You're solving for v.


Anybody free to verify this answer?  ^_^

shane_b · Answer

$$0.12(200)+0.40x=0.32(200+x)$$$$24+0.40x=64+0.32x$$$$0.40x-0.32x=64-24=40$$$$0.08x=40$$$$x=500$$So it will take 500mL of solution B to obtain a mixture of 32%.