The aim of this study is to explore the judgments and reasoning in probabilistic tasks that require comparing two probabilities either with or without introducing an additional degree of uncertainty. The reasoning associated with the task having an additional condition of uncertainty has not been discussed in previous studies. The 66 undergraduate students, participants in this study, used an analytic process for the task without an additional condition of uncertainty and a heuristic for the task with it. The findings show that they focused on the most likely event and derived a prediction based on this event that, in some cases, led them to answer incorrectly. The educational implications include a gradual method for developing better intuition for the students to help them tackle similar problems in the future.