BITSAT 2017 Slot 2 Solved Paper

In Young's double slit experiment, the slits are 2mm apart and are illuminated by photons of two wavelengths λ1=12000Å and λ2=10000Å. At what minimum distance from the common central bright fringe on the screen 2m from the slit will a bright fringe from one interference pattern coincide with a bright fringe from the other?