Diffusion Questions

Two gases $A$ and $B$ having the same volume diffuse through a porous partition in $20$ and $10$ seconds respectively. The molecular mass of $A$ is $49\text{u}$. Molecular mass of $B$ will be:

$50\text{mL}$ of each gas $A$ and of gas $B$ takes $150$ and $200$ seconds respectively for effusing through a pin hole under the similar conditions. If molecular mass of gas $B$ is $36$, the molecular mass of gas $A$ will be: