The solution of the problem 3.22 кр 3 from the problem

The solution of the problem 3.22 кр 3 from the problem

PROBLEM 3.22
In Young´s experiment, one of the slits was covered by a transparent plate 11 microns thick,
The central light stripe shifted to a position initially occupied by the tenth light stripe.
Find the refractive index of the plate if the wavelength of light is 0.55 μm.