The main purpose of this study is to find out the shortest path(minimize total travel distance) of the vehicle routing problem with possible service time windows. This study suggests a mathematical programming model and verifies the suggested mathematical programming model by using CPLEX 11.1. This study also suggests a hybrid genetic algorithm which considers the generation for an initial solution by random and saving algorithm, the process of solution improvement by 2-Opt. The suggested algorithm is compared by Solomon's examples considering possible service time windows. We found the better solutions concerning total travel distance rather than best-known solutions in R/RC-type Solomon's examples.