Q: A can do a work in 9 days, B can do a work in 7 days, C can do a work in 5 days. A works on the first day, B works on the second day and C on the third day respectively that is they work on alternate days. When will they finish the work ?

• A. [7 + (215/345)] days
• B. [6 + (11/215)] days
• C. [6 + (261/315)] days
• D. [5 + (112/351)] days