The correct option is D 16 days
Given,
For 200 men, the provision will last for 20 days.
We know that if the number of men increase, the provision will last for lesser days.
So, Number of men(x)∝1Number of days(y)
∴x1x2 = y2y1
Given,
x1 = 200 men
y1 = 20 days
x2 = 200+50=250 men
and y2 = no. of days for which the provision will last for 250 men
⇒ y2 = x1 × y1x2
⇒ y2 = 200 × 20250 = 16 days
Hence, the provision will last for 16 days if 50 more men joined the fort.