Translate the following inference to logic notation: If Richard works, then Patricia is a doctor. If Patricia were a doctor, then Elisabeth is a mechanic. If Linda were a police officer, then Elisabeth is a mechanic. Robert is bored or Linda is a police officer. If Robert were bored, then Richard is working. Therefore Elisabeth is a mechanic.
p -> q. q -> r. s -> r. t or s. t -> p. Therefore r.