  A measurement of the inclusive semileptonic branching ratios of b hadrons
produced in Z decay is presented, using four million hadronic events collected
by the ALEPH detector from 1991 to 1995. Electrons and muons are selected
opposite to b-tagged hemispheres. Two different methods are explored to
distinguish the contributions from direct $\bl$ and cascade $\bcl$ decays to
the total lepton yield. One is based on the lepton transverse momentum
spectrum, the other makes use of the correlation between the charge of the
lepton and charge estimators built from tracks in the opposite hemisphere of
the event. The latter method reduces the dependence on the modelling of
semileptonic b decays. The results obtained by averaging the two techniques are
BR(b->l) = 0.1070 +- 0.0010 +- 0.0023 +- 0.0026 BR(b->c->l) = 0.0818 +- 0.0015
+- 0.0022 + 0.0022 -0.0014
