(A): The Pressure of the gas increases with the decrease in volume at constant temperature.

(R): Number of molecules per unit volume increases with decrease in Volume consequently number of collisions on the wall increases.

Given Data: Two statements are given. We have to tell if they are correct and interrelated to one another or not.

Detailed Solution: We know that if the volume of the container is decreased,the gas molecules have less space to move around. As a result, they will strike the walls of the container more often, and the pressure increases.

Therefore, option (A) is the answer.