Gravitational lensing (GL) provides the sudden changes in flux densities, when a compact source crosses a critical curve. Due to lensing, the image of the lensed object is split into at least two images, and merged together upon the source crossing the critical curve. Light paths of the images differ from one another’s, so results time delay to the observer. Asymmetric light curves and the time delay in lensing contain astrophysical information on the GL system: e.g. source structure, density distribution, and cosmological distance scale. The disalignment of GL system, b, is an important parameter in the GL analysis. We derive b as a function of density parameter of gravitational lens mass. We present an analytical formulation to determine cosmological distance scales, hence the Hubble parameter, and other properties of GL system. We also discuss degeneracies in the GL mapping.