Two boats are travelling away from each other in opposite directions. One boat is travelling east at the constant speed of \(8\) km/h and the other boat is travelling west at a different constant speed.
At one point, the boat travelling east was \(200\) m east of the boat travelling west, but \(15\) minutes later they lose sight of each other.
If the visibility at sea that day was 5 km, determine the constant speed of the boat travelling west.
Theme: Number Sense