Write a system of equations to describe the situation below, solve using substitution, and fill in the blanks. Two sisters have decided to watch all the episodes of a popular TV show on DVD. Laura has already watched 2 episodes and will continue to watch the show at a rate of 2 episodes per day. Julia, who hasn't yet seen the show, will start watching 4 episodes per day. Once the two sisters get to the point where they plan to finish the series together. How long will that take? How many episodes will each sister have watched at that point? In ___days, the sisters will each have watched ___episodes of the show.