  A time-dependent phenomenological model of $\Lambda$, viz. $\dot \Lambda\sim
H^3$ is selected to investigate the $\Lambda$-CDM cosmology. Time-dependent
form of the equation of state parameter $\omega$ is derived and it has been
possible to obtain the sought for flip of sign of the deceleration parameter q.
Present age of the Universe, calculated for some specific values of the
parameters agrees very well with the observational data.
