  The model recently proposed by A.A. Shanenko [Phys. Lett. A 227 (1997) 367]
is used to derive linear integro-differential equations whose solutions provide
reasonable estimates for the momentum distribution and condensate fraction in
interacting many-boson system at zero temperature. An advantage of these
equations is that they can be employed in the weak coupling regime and beyond.
As an example, analytical treatment of the weak coupling case is given.
