At \( 600\,\mathrm{K} \), the root mean square (rms) speed of gas \( X \) (molar mass \( = 40 \)) is equal to the most probable speed of the gas \( Y \) at \( 90\,\mathrm{K} \). The molar mass of gas \( Y \) is _____ \( \mathrm{g\,mol^{-1}} \). (Nearest integer)
