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?
Choose the correct choice from the following options
A) 21 days B) 24 days C) 23 days D) 25 days E) 26 days
24 days   24 days   10/40 + 10/30 + 10/x = 1   x = 24 days
<result>B</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?