A solution of ` 9%` acid is to be diluted by adding `3%` acid solution to it. The resulting mixture is to be more then ` 5%` but less than ` 7%` acid. If there is 460 L of the ` 9%` solution, how many litres of ` 3%` solution will have to be added?

Explanation

To solve the problem step by step, we need to set up the inequalities based on the information given.

### Step 1: Define the Variables
Let \( x \) be the amount of 3% acid solution to be added (in liters).

### Step 2: Calculate the Amount of Acid in Each Solution
- The amount of acid in the 460 L of 9% solution:
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