This paper considers the problem of calculating the propagation of acoustic waves within an ideal isotropic multilayer plate structure. In such a situation the process of mode conversion as the wave interacts with each interface of the plate creates an ever increasing number of waves to track, and to perform calculations on, as the wave propagates within the layered media. Exploring this problem by examining the ray paths of the multiple reflections within the plate structure, it is possible to show that upon careful consideration many of these paths will travel equivalent distances in time and space becoming coincident. The principle of superposition can then be used to combine these coincident paths, this superposition reduces the number of waves to track, and simplifies the problem so that the necessary calculations can be performed in a time efficient manner.