In a single-slit diffraction experiment, light of wavelength ${\lambda }_1$ passes through a single slit of width $w_1$ to project a diffraction pattern onto a screen at distance $D$. The width of the central maximum is measured to be $W$.

The apparatus is modified: the light source is replaced with one of wavelength ${\lambda }_2=1.25{\lambda }_1$, and the slit width is reduced to $w_2=0.50w_1$, while the screen distance $D$ remains unchanged.

What is the new width of the central maximum on the screen, assuming the small-angle approximation holds?