# A 280 mL solution is 20% salt. How much water should be added to make the solution 14% salt?

##### 1 Answer

You need to add **120 mL** of water.

#### Explanation:

The key to this problem is to realize that the amount of solute you started with **remains unchanged** after the solution is diluted.

In essence, the amount of salt you had in the first solution will be found in the final solution as well.

This means that you can determine how much water to add to the first solution by first calculating how much salt you have

This means that

Let's say that *mass of the solution*.

This means that you can write

Solve for

So, if you add **120 mL** of water to 280 mL of a 20% salt solution, you will get a final solution that is 14% salt.