In Young's double slit experiment, the intensity on the screen at a point where path difference is $\lambda$ is $K$. What will be the intensity at the point where path difference is $\frac{\lambda }{4}$?

The figure shows a double-slit experiment, where $P$ and $Q$ are the slits. The path lengths $PX$ and $QX$ are $n\lambda$ and $(n+2)\lambda$, respectively, where $n$ is a whole number and $\lambda$ is the wavelength. Taking the central fringe as zero, what is formed at $X$?