  Compact expressions for the average subentropy and coherence are obtained for
random mixed states that are generated via various probability measures.
Surprisingly, our results show that the average subentropy of random mixed
states approaches to the maximum value of the subentropy which is attained for
the maximally mixed state as we increase the dimension. In the special case of
the random mixed states sampled from the induced measure via partial tracing of
random bipartite pure states, we establish the typicality of the relative
entropy of coherence for random mixed states invoking the concentration of
measure phenomenon. Our results also indicate that mixed quantum states are
less useful compared to pure quantum states in higher dimension when we extract
quantum coherence as a resource. This is because of the fact that average
coherence of random mixed states is bounded uniformly, however, the average
coherence of random pure states increases with the increasing dimension. As an
important application, we establish the typicality of relative entropy of
entanglement and distillable entanglement for a specific class of random
bipartite mixed states. In particular, most of the random states in this
specific class have relative entropy of entanglement and distillable
entanglement equal to some fixed number (to within an arbitrary small error),
thereby hugely reducing the complexity of computation of these entanglement
measures for this specific class of mixed states.
