Estimation of path duration in MANET's is useful and it can be used in various ways to improve the performance of communication in MANET's. One such application is the assignment of optimum route cache TTL for "on demand" routing protocols which helps to improve the routing protocol's performance significantly. Estimation of path duration becomes difficult due to the random nature of mobile nodes. This thesis provides a way to estimate average path duration for a n-hop path in mobile adhoc networks. Random Way Point (RWP) model is used as it is the most largely deployed and accepted model. The accuracy of the proposed analytical model is verified by comparing the analytical results with the experimental results available in literature. This thesis also considers a network parameter "node density" and provides the results of the impact of "node density" on path duration.