In the third question, are the two walkers moving at a constant speed?

It's obvious that the speeds of the two walkers are identical, but are they also constant as they move along the legs of the triangle?

That is to say if the triangle's area is increasing by 5 square meters per second at the very beginning, it would continue to increase faster at a rate proportional to half of the square of the distance traveled?

Or does it mean that the area always increases at a rate of 5 square meters per second and that the walkers' speeds slow over time while remaining identical to one another to fulfill that condition?

Sorry, it seems a bit unclear to me as I'm trying to work it out.