A can do a piece of work in 4 days. B can do it in 5 days. With the assistance of C they completed the work in 2 days. Find in how many days can C alone do it?
Choose the correct choice from the following answers:
A) 88	B) 20	C) 99	D) 18	E) 11
Explanation:   C = 1/2 - 1/4 - 1/5 = 1/20 =&gt; 20 days   Answer:20
<result>B</result>
A can do a piece of work in 4 days. B can do it in 5 days. With the assistance of C they completed the work in 2 days. Find in how many days can C alone do it?