The person Metrocles studied under presided over the Peripatetic school for how many years?
Metrocles:  He studied in Aristotle’s Lyceum under Theophrastus, and eventually became a follower of Crates of Thebes who married Metrocles’ sister Hipparchia. Theophrastus:  Theophrastus presided over the Peripatetic school for thirty-six years, during which time the school flourished greatly.
thirty-six