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 answer
A) 10 days B) 20 days C) 5 days D) 4 days E) 3 days
Explanation:   C = 1/2 - 1/4 - 1/5 = 1/20 =&gt; 20 days   Answer: Option 20 days
<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?