You are provided a slide having two slits cut into it and asked how far apart the slits are. You shine white light on the slide and observe that the first-order color spectrum which is created on a screen 3.75 m away. On the screen, the red light having a wavelength of 720 nm is separated from the violet light having a wavelength of 403 nm by 6.20 mm. Determine the separation of the two slits?