Final answer:
The statement 'At a constant temperature, the volume of a gas varies inversely as the pressure' can be expressed as the equation V = k/P, where k is the constant of variation.
Step-by-step explanation:
The student's question is related to the inversely proportional relationship between the volume (V) and pressure (P) of a gas, as described by Boyle's Law. To express this relationship as an equation with a constant of variation (k), we use the formula:
V = k/P
Here, k represents the constant of variation and maintains a consistent value for a fixed amount of gas at a constant temperature. As volume increases, pressure decreases, and vice versa, in such a way that their product remains constant.