A and B can do a piece of work in 4 days, B and C can do the same work in 5 days, A and C can do it in 10 days. If A, B, C work together, in how many days can they complete the work ?

Correct option is C

Given:
A and B can complete the work in 4 days.
B and C can complete the work in 5 days.
Formula Used:
Total Work = Efficiency × Total Time
Solution:
Let the total work be 20 units