If the passenger were at rest, his speed relative to the shore will be identical to the boat's, as follows:
vps = vbr + vrs
As he is moving in a direction opposite to the boat's, his velocity relative to the shore must be less than if he were at rest, in the same quantity that he was moving opposite to the boat, as follows:
As it mostly occurs on a surface where an ecosystem has previously existed. Primary succession only occurs on a surface where no ecosystem existed ever before!
80 km per hour i believe. i’ll admit i’m american so we don’t use km lol, but the math should be the same. total distance = 120km, and total time = 1.5 hours. 120/1.5 = 80.
