A freighter needs to travel up the Savannah River to the port, moving against the flow of the water.

If the river flows at 3 m/s relative to the shore, and the maximum speed of the freigñter relative

to the river is 7 m/s, what is the maximum velocity of the freighter relative to the shore?

-4 m/s

Step-by-step explanation:

The maximum speed of the river relative to the shore is 3 m/s. Its velocity is + 3 m/s

The maximum speed of the freighter relative to the river is 7 m/s since it moves in the opposite to direction to the flow of the river, its velocity is - 7 m/s.

The velocity of the freighter relative to the shore = velocity of the freighter relative to the river + velocity of the river relative to the shore = - 7 m/s + 3 m/s = - 4 m/s