A and B can do a piece of work in 10 days. With the help of C they finish the work in 3 days. C alone can do that piece of work in?  Choose the correct choice from the following answers:
A) 15.5 days
B) 4.3 days
C) 17.5 days
D) 16.5 days
E) 18.5 days
C = 1/3 – 1/10 = 7/30 =&gt; 4.3 days   ANSWER:4.3 days
<result>B</result>
A and B can do a piece of work in 10 days. With the help of C they finish the work in 3 days. C alone can do that piece of work in?