A and B can do a piece of work in 7 days. With the help of C they finish the work in 5 days. C alone can do that piece of work in?  Choose the correct option: A) 11 days B) 77 days C) 30 days D) 88 days E) 17 days
30 days = 1/5 – 1/6 = 1/30 =&gt; 30 days   Answer:30 days
<result>C</result>
A and B can do a piece of work in 7 days. With the help of C they finish the work in 5 days. C alone can do that piece of work in?