Elise and Kenji are making presentations for a class project. Elise's slideshow starts with a verbal introduction that is 14 seconds long, and then each slide is left up for 4 seconds. Kenji leaves each slide onscreen for 7 seconds, and his introduction lasts 5 seconds. Elise and Kenji notice that their presentations have both the same number of slides and the same duration. How long is each presentation? How many slides are in each presentation?