An ion with mass number `56` contains `3` units of positive charge and `30.4%` more neutrons then electrons. Assign the symbol to this ion.

Explanation

To solve the problem step by step, we need to determine the symbol of the ion with the given characteristics.

### Step 1: Understand the given information
- Mass number (A) = 56
- Positive charge = +3
- Neutrons are 30.4% more than electrons.

### Step 2: Define variables
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