Write a system of equations to describe the situation below, solve using substitution, and fill in the blanks. Darell and Rafi are making presentations for a class project. Darell's slideshow starts with a verbal introduction that is 18 seconds long, and then each slide is left up for 5 seconds. Rafi leaves each slide onscreen for 4 seconds, and his introduction lasts 19 seconds. Darell and Rafi 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?

Each presentation has
slides and is
seconds long.