Hello Shahana

The answer would have the following steps.

The root mean square velocity of a gas is given by:
v(rms) = √[3kT/M]
For two different gases 1 and 2 with two molecular weights M1 and M2, we can find the ratio:
v1/v2 = √[3kT/M1] /√[3kT/M2]
This reduces to:
v1/v2 = √[M2/M1]
Notice this is equivalent to Graham's law. Just substitute:
v(CH4)/v(SO2) = √[64/16] = 2.
The methane molecules go twice as fast.

Hope it helps you.