Working together A and B can do a job in 6 days. B & C can do the same job in 10 days while C and A can do it in 7.5 days. How long will it take if all A, B,C work together to complete the job? How long will it take for A alone, B alone, C alone to complete the job?
A,B,C combine will complete the job in 3 4/7 days. From here you may calculate the individual compleion time