The pressure of a given mass of a gas filled in a vessel of volume V at constant temperature is reduced to `1//3` rd of its initial value. Calculate the percentage change in its volume.

Explanation

To solve the problem of calculating the percentage change in the volume of a gas when its pressure is reduced to one-third of its initial value at constant temperature, we can follow these steps:

### Step 1: Understand the Initial Conditions
Let the initial pressure of the gas be \( P_1 \) and the initial volume be \( V_1 = V \).

### Step 2: Determine the New Pressure
The new pressure \( P_2 \) is given as one-third of the initial pressure:
\[
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