A can do a piece of work in 20 days; B can do the same in 30 days. A started alone but left the work after 10 days, then B worked at it for 10 days. C finished the remaining work in 10 days. C alone can do the whole work in?	Pick:
A) 24 days B) 60 days C) 86 days D) 45 days E) 17 days
10/20 + 10/30 + 10/x = 1   x = 60 days   Answer:60 days
<result>B</result>
A can do a piece of work in 20 days; B can do the same in 30 days. A started alone but left the work after 10 days, then B worked at it for 10 days. C finished the remaining work in 10 days. C alone can do the whole work in?