The ebbinghaus model of human memory may be used to model the amount of acquired knowledge a college student will retain after “cramming” for a final exam. the formula is p=(100-a)e^-b(0.07), where a and b vary from one person to another, and p is the percent of retained knowledge 1/2 day later when the student actually takes the final exam. if a = 20 and b = 1.2 for a typical student, how much of their “crammed” knowledge will that student retain at the moment of taking the final exam?