Kira and Marvin are making presentations for a class project. Kira's slideshow starts with a verbal introduction that is 13 seconds long , and then each slide is left up for 4 seconds. Marvin leaves each slide onscreen for 3 seconds, and his introduction lasts 14 seconds. Kira and Marvin notice that their presentations have both the same number of slides and the same duration . How many slides are in each presentation ? How long is each presentation?