Sunny, Nikki and Rohan are working on their dream project after 4 days of working they had an argument. so that, Sunny left the work. The remaining work is continued by Nikki and Rohan. Nikki left the work 2 days before the completion of the project. How many days work is completed if Sunny, Nikki and Rohan separately complete the project in 15, 20 and 30 days respectively