Abstract:
A finite non-nilpotent group is called a $B$-group if all proper subgroups of its quotient group by the Frattini subgroup
are primary. A finite group whose Sylow subgroups are all cyclic is called a $z$-group. We study a finite group $G$ that can be
represented as a product of its $B$-subgroup and $z$-subgroup of coprime orders. For a solvable groups $G$, we prove that the second
derived subgroup is nilpotent, the derivative length of the quotient group by the Frattini subgroup does not exceed three, and the
$p$-length is at most two. If $G$ is a simple group, then $G$ is isomorphic to determined.