Answer:
The new pressure becomes one third of the initial pressure.
Explanation:
The relation between pressure and volume at constant temperature is given by :
[tex]P\propto \dfrac{1}{V}\\\\P=\dfrac{1}{V}[/tex]
Let new pressure and volume be P' and V' respectively.
V'=3V (given)
So,
[tex]P'=\dfrac{1}{V'}\\\\=\dfrac{1}{3V}\\\\=\dfrac{1}{3}\times \dfrac{1}{V}\\\\P'=\dfrac{1}{3}\times P[/tex]
Hence, new pressure becomes one third of the initial pressure.