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 options:
A) 10
B) 20
C) 30
D) 40
E) 15
C= 1/2-1/4-1/5   =1/20   =20days   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?