Translate the following inference to logic notation: If Susan listens to a song, then Jennifer is bored. If Jennifer were bored, then Susan is listening to a song. If Elisabeth reads a book, then Susan is listening to a song. If Jennifer were bored, then Elisabeth is reading a book. Therefore Susan is listening to a song if and only if Jennifer is bored.
p -> q. q -> p. r -> p. q -> r. Therefore p <-> q.