A can do a piece of work in 40 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?  Choices
A) 24  B) 77  C) 66  D) 89  E) 12
10/40 + 10/30 + 10/x = 1   x = 24 days   24nswer:24
<result>A</result>
A can do a piece of work in 40 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?