29.

(a) A fire station is to be located along a road of length A, A < ∞. If fires will occur at points uniformly chosen on (0, A), where should the station be located so as to minimize the expected distance from the fire? That is, choose a so as to minimize E[X - a]

when X is uniformly distributed over (0, A).

(b) Now suppose that the road is of infinite length-stretching from point 0 outward to ∞. If the distance of a fire from point 0 is exponentially distributed with rate λ, where should the fire station now be located?

That is, we want to minimize E[|X - a|] where X is now exponential with rate λ.