Hello!!

According to your question temperature is kept constant and mean free path is doubled thus,

Proceeding-

Solution :

λ∝1/P
When mean free path is doubled, pressure becomes half.

So the answer would be simply p/2.

I really hope this helps you!!

Thank you!!

The mean free path is the distance that a molecule travels between collisions.

Let us denote it with L.

Now , after looking at the formula of mean free path , we can say that pressure is inversely proportional to mean free path.

Therefore , when mean free path of atom is doubled , pressure will become halved .

L =2x , then P= x/2.