A river current has a velocity of 5 km/h relative to the shore. A boat moves in the same direction as the current at 4 km/h relative to the river. How do you calculate the velocity of the boat relative to the shore?
subtract the boat’s velocity from the river’s velocity
add the river’s velocity to the boat’s velocity
divide the river’s velocity by the boat’s velocity
subtract the boat’s velocity from the river’s velocity
add the river’s velocity to the boat’s velocity
divide the river’s velocity by the boat’s velocity