1. The problem statement, all variables and given/known data Two slits are 0.158mm apart. A mixture of red light (wavelength = 665nm) and yellow-green light (wavelength = 565nm) fall onto the slits. A screen is located 2.2m away. Find the distance between the third-order red fringe and the third-order yellow-green fringe. 2. Relevant equations Since they ask for colored fringes, and not dark ones, it must be constructive interference. x/L = (m*λ/ d) x = 0.000158m L = 2.2m m = 3 (third order fringe) λ of red = 6.65E-7m λ of yellow-green = 5.65E-7m 3. The attempt at a solution I did the equation twice, once for each wavelength. For red I got x as 2.7E-2m, and for yellow-green i got x as 2.36E-2m. The difference between these 2 values is 0.0034mm or 3.4mm. The answer however, is supposed to be 28mm. . . How was I supposed to do this?