The pressure P, volume V, and absolute temperature T of a given mass of an ideal gas change simultaneously…

Analyze the question: P, V and T all change together for a fixed mass of ideal gas. This calls for the combined gas law.

Concept: Combining Boyle's law (PV = constant at constant T) and Charles's law (V/T = constant at constant P) gives:

PV/T = constant, or P₁V₁/T₁ = P₂V₂/T₂

Check each option:

• A. PV = constant/T means PV × T = constant. This is wrong, because PV is proportional to T, not inversely proportional.
• B. P/T = constant holds only if V is fixed (Pressure law). V is changing here, so it is not generally true.
• C. P/V = constant/T means PT/V = constant. This is wrong.
• D. The "I" in "I/T" is almost certainly a typo for "1", so the option reads 1/T = constant/(PV). Cross-multiplying gives PV = constant × T, which means PV/T = constant. This matches the combined gas law.

Answer: Option D is the correct one, assuming "I" is a typo for "1".

Tip: When P, V and T all change, think "PV over T is constant". Any equivalent rearrangement is correct, so check options by rearranging them back to PV/T = k. Also, for Nigerian exam papers, typos like "I" for "1" appear fairly often, so read the option in the way that makes sense.