Two gases are sent through 2 ends of a 2m long pipe. If the gases reach at a distance of 1.5m from the end of the lighter gas, then what is the ratio of their masses (lighter: heavier), assuming pressure conditions to be the same?

Question

(A) $\large\frac{1}{3}$ (B) $\large\frac{1}{9}$ (C) $\large\frac{1}{27}$ (D) $\large\frac{1}{\sqrt 3}$