Find the percentage decrease in the weight of the body when taken `64 km` below the surface of the Earth. Take redius of the Earth `= 6400 km`.

Explanation

To find the percentage decrease in the weight of a body when taken 64 km below the surface of the Earth, we will follow these steps:

### Step 1: Understand the relationship between weight and gravity
The weight of a body is given by the formula:
\[ W = mg \]
where \( W \) is the weight, \( m \) is the mass of the body, and \( g \) is the acceleration due to gravity.

### Step 2: Calculate the acceleration due to gravity at the surface of the Earth
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