  We present theoretical evidence that the exclusive/inclusive ratio of
semileptonic $\Lambda_b$-decays exceeds that of semileptonic B-decays where the
experimental exclusive/inclusive ratio amounts to about 66%. We start from the
observation that the spectator quark model provides a lower bound on the
leading order Isgur-Wise function of the $\Lambda_b \to \Lambda_c$ transition
in terms of the corresponding $B \to D,D^*$ mesonic Isgur-Wise function. Using
experimental data for the $B \to D,D^*$ mesonic Isgur-Wise functions this bound
is established. Applying a Bethe-Salpeter model including spectator quark
interactions and a QCD sum rule estimate of the $\Lambda_b \to \Lambda_c$
transition form factor which satisfy the spectator quark model bound we predict
the exclusive/inclusive ratio of semileptonic $\Lambda_b$ decay rates to lie in
a range between 0.81 and 0.92. We also provide an upper bound on the baryonic
Isgur-Wise function which is determined from the requirement that the exclusive
rate should not exceed the inclusive rate.
