An LPG (Liquified Petroleum Gas) cylinder weighs 15.0 kg when empty. When full, it weighs 30.0 kg and shows a pressure of 3.0 atm . In the course of usage at \(27^{\circ} \mathrm{C}\), the mass of the full cylinder is reduced to 24.2 kg . The volume of the used gas in cubic metre at the normal usage condition ( 1 atm and \(27^{\circ} \mathrm{C}\) ) is (assume LPG to be normal butane and it behaves ideally)

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.