The average atomic mass of copper is `63.5`. It exists as two isotopes which are `._(29)^(63)Cu and ._(29)^(65)Cu`. Calculate the percentage of each isotope present in it.

Explanation

To solve the problem of determining the percentage of each copper isotope present in the average atomic mass of copper (63.5), we can follow these steps:

### Step-by-Step Solution:

1. **Define Variables**:
Let the percentage of the isotope \( ^{63}Cu \) be \( x \). Therefore, the percentage of the isotope \( ^{65}Cu \) will be \( 100 - x \).

2. **Set Up the Average Atomic Mass Equation**:
...