A soap film (n = 1.33) is 465 nm thick and lies on a glass plate (n

Question:

A soap film (n = 1.33) is 465 nm thick and lies on a glass plate (n = 1.52). Sunlight, whose wavelengths (in vacuum) extend from 380 to 750 nm, travels through the air and strikes the film perpendicularly. For which wavelength(s) in this range does destructive interference cause the film to look dark in reflected light?