M, N and O alone can complete a work in 30, 36 and 45 days respectively. All three of them started the work together but after 4 days M left the work and N left the work 9 days before the work was completed. O completed the remaining work alone. In how many days was the total work completed?
1
67/3 days
2
71/3 days
3
61/3 days
4
73/3 days