The correct option is C 16 days
The number of men (N) employed to complete a piece of work is inversely proportional to the number of days (D).
⇒N∝1D
Let the constant of variation be k.
⇒N=kD
⇒ND=k
Given, when N = 200 men , D = 4 days.
So, k=ND=(200)(4)=800
⇒N=800D
Hence, the time required (D) to complete the same work by 50 men =80050=16 days.