A and B can do a piece of work in 10 days. With the help of C they finish the work in 5 days. C alone can do that piece of work in?	Options:
A) 33	B) 878	C) 30	D) 10	E) 11
C = 1/5 â€“ 1/10 = 1/10 =&gt; 10 days   Answer: 10
<result>D</result>
A and B can do a piece of work in 10 days. With the help of C they finish the work in 5 days. C alone can do that piece of work in?