An exam is given in a certain class

An exam is given in a certain class. The average (arithmetic mean) of the highest score and the lowest score is equal to x. If the average score for the entire class is equal to y and there are z students in the class, where z > 5, then in terms of x, y, and z, what is the average score for the class excluding the highest and lowest scorers?

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · test #19