B can do a certain work in 40 days. B is 20% less efficient than A and C is 50% less efficient than B. All the three started the work together. If C and B left the work 4 days and 2 days before the completion of the work, respectively, then in how many days was the entire work completed?
1
15 days
2
20 days
3
18 days
4
16 days