P, Q and R can complete a work alone in 12,15 and 20 days respectively. They started the work together. P left the work 8 days before the work was completed and Q left the work 5 days after P had left. R completed the remaining work alone. How many days will be required to complete the whole work?
1
32/3 days
2
10 days
3
28/3 days
4
25/3 days