Problem (3): In a certain college town, 25% of the students failed Mathematics, 15% failed Chemistry, and 10% failed both Mathematics and Chemistry. A student is selected at random: a) If the student failed Chemistry, what is the probability that he/she failed Mathematics? b) What is the probability that the student failed Mathematics or Chemistry? c) What is the probability that the student failed neither Mathematics nor Chemistry? Let M denotes to Mathematics and let C denotes to Chemistry.