How long will it take for a raft to travel 12 km along the river if the speed of the river is 0.25 m / s.

If we assume that the speed of the river is constant, then the time of movement of the raft along the river is calculated by the formula:
t = S / V, where S is the distance covered by the raft (S = 12 km = 12 * 10³ m), V is the speed of the river (V = 0.25 m / s).
Let’s calculate the time of movement of the raft:
t = S / V = 12 * 10³ / 0.25 = 48000 s = 800 min = 13.3 h.
Answer: The raft will pass 12 km along the river in 13.3 hours.