  The lifetime of an unstable state or resonance formed as an intermediate
state in two body scattering is known to be related to the dwell time or the
time spent within a given region of space by the two interacting particles.
This concept is extended to the case of three body systems and a relation
connecting the three body dwell time with the two body dwell times of the
substructures of the three body system is derived for the case of separable
wave functions. The Kapur Peierls formalism is revisited to discover one of the
first definitions of dwell time in literature. An extension of the Kapur
Peierls formalism to the three body case shows that the lifetime of a three
body resonance can indeed be given by the three body dwell time.
