college algebra

Question

You need a 50% alcohol solution. On hand, you have a 350 mL of a 90% alcohol mixture. How much pure water will you need to add to obtain the desired solution?Write an equation using the information as it is given above that can be used to solve this problem. Use as your variable to represent the amount of pure water you need to use.

equation?

? mL of pure water

? mL of the desired 50% solution

Answer 1

The alcohol content is:

350 * 0.9 + 0*x = 0.5(x+350)

315 = 0.5x + 175

140 = 0.5x

x=280

use all of the 90% alcohol solution and

280 mL of water