Question

How many ounces of pure (distilled) water should a chemist add to an 80%

Answer 1

We want to see how much pure water and 80% salt solution should be mixed to get 20 ounces of a 50% salt solution, we will solve this by using a system of equations. We will see that we need to use 7.5 ounces of pure water and 12.5 ounces of the 80% salt solution.

How to get the system of equations?

We should start by defining the variables we will be using, these are:

• x = ounces of pure water used
• y = ounces of the 80% solution used.

We know that we want to end with 20 ounces of the mixture, then we have:

x + y = 20

We also know that the percentage of salt in the final mixture must be 50%, which means that a 0.5 of the final mixture is salt, then we have:

0*x + 0.8*y = 0.5*20

(the first 0 is because we have no salt in the pure water, and the 0.8 is because we have 80% of salt in the 80% mixture)

So we got the two equations needed, thus the system of equations is:

x + y = 20

0*x + 0.8*y = 0.5*20

With the second one we can get the value of y:

0*x + 0.8*y = 0.5*20

0.8*y = 0.5*20 = 10

y = 10/0.8 = 12.5

This means that we must use 12.5 ounces of the 80% solution, and we need to use:

x = 20 - y = 20 - 12.5 = 7.5

7.5 ounces of pure water.

If you want to learn more about systems of equations, you can read:

brainly.com/question/13729904