Areversible reaction at equilibrium can counteract the stress of an increase in pressure by:

A reversible reaction at equilibrium can counteract the stress of an increase in pressure by displacing the equilibrium toward the side where the number of molecules of gases will be fewer.

Given that the pressure is directly proportional to the number of molecules of gas, by driving the reaction toward the side where the number of molecules decreases the pressure will be relief, at least partially.

This is a classical application of Le Chatelier's principle.

Ithink it is quantity of plants

You would do 1500/4 and the answer is 375