Problem: You perform the double slit experiment using a slide with 0.04 mm slits. You choose to use the double slit with a 0.250 mm separation and set the slide up 1.25 m from the screen. With a red laser of wavelength 652 nm you measure the bright fringe separation. From center to center how far apart will 6 of these bright fringes be? You also decide to place a small piece of tape on the slide covering up one of the slits.

Part A: What should the spacing between two dark bands be now?

I need the right answer and steps of solving this problem. Thanks!