A contractor undertook a project to complete it in 20 days which needed 5 workers to work continuously for all the days estimated. But before the start of the work the client wanted to complete it earlier than the scheduled time, so the contractor decided to increase 5 additional men every 2 days to complete the work in the time as the client desired. Not it happened that the work was further increased by 50% but the contractor continued to increase 5 workers after every 2 days then how many more days are required over the initial time specified by the client.