meter bridge Questions

In a metre bridge experiment, a null point is obtained at $20\text{cm}$ from one end of the wire when resistance $X$ is balanced against another resistance $Y$. If $X<Y$, then where will be the new position of the null point from the same end, if one decides to balance a resistance of $4X$ against $Y$?

Shown in the figure is a meter-bridge setup with null deflection in the galvanometer. One resistor is $55\Omega$ and the balancing length from left is $20\text{cm}$. The value of the unknown resistor $R$ on the right side is: