Integrating mobile adhoc network (MANET) to the Internet is a burning issue due to its various advantages over standalone MANET. Such integration provides many usage scenarios for both fixed network and MANET together like conference meeting, wireless classroom and information processing on the move such as in trains and airport. Some of the nodes in MANET called Internet gateways (IGWs) act as an interface between MANET and fixed network such as Internet which offer the Internet connectivity to the mobile host. Such integrated network is called hybrid MANET. A mathematical model has been proposed in this paper to calculate end to end (ETE) delay and throughput between active source and each IGW node by splitting the traffic in multiple paths. The proposed model follows M/M/m queuing network and Burke theorem has been used to calculate ETE delay of multiple paths between active source (AS) and each IGW. Further, through analysis the best Internet gateway is selected based on minimum ETE delay between AS and each IGW for data delivery to the Internet. The proposed model is useful for analyzing and selecting IGW out of multiple IGWs in hybrid MANET. Simulation results show the validity of the proposed approach.