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 choice from the following answers:
A) 76 days
B) 86 days
C) 30 days
D) 57 days
E) 46 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?