In this paper, we evaluate the expectation values of four-quark operators for
the inclusive beauty decays from the differences in the inclusive total decay
rates, assuming that the heavy quark expansion converges at O(1/m3). The
obtained expectation values yeilds the ratio τ(Λb)/τ(B) close to
the experimental onee. We further point out that the quark-hadron duality
violation would be rather small allowing predictions of inclusive quantities.Comment: 5 pages, typos corrected, version to be published in PL