Answer: b) they loaded 112356 lbs of cargo
Step-by-step explanation:
When a boat or an object floats in water, the volume of water that it displaces is equivalent to its weight.
When moving into the port, the cargo boat displaced 2200 ft³ of water. Since the density of water is 62.42 lb/ft³ and mass = density × volume, then the mass of the cargo boat on entering the port is
2200 × 62.42 = 137324 lbs
On leaving the port, it displaces 4000 ft³ of water. The mass of the cargo boat on leaving the port is
4000 × 62.42 = 249680 lbs
The difference in both masses is
249680 - 137324 = 112356 lbs
Therefore, they loaded 112356 lbs of cargo