A and B can do a piece of work in 10 days, B and C in 15 days and C and A in 20 days. C alone can do the work in :A60 daysB80 daysC120 daysD30 daysAnswer: C. 120 daysRead Explanation:A+B+C -------->13/2 A+B-------->6 efficiency of C---->1/2Open explanation in App