Two narrow slits are used to produce a double-slit interference pattern with monochromatic light ( = 450

Two narrow slits are used to produce a double-slit interference pattern with monochromatic light (λ = 450 nm). The slits are separated by 0.90 mm, and the interference pattern is projected onto a screen 7.5 m away from the slits.
(a) What is the distance between two nearby bright fringes on the screen?
(b) What is the distance between two nearby dark fringes on the screen? Assume the fringes are near the center of the interference pattern.