Acan contains 18 marbles six red, four white, three blue, and five black, one marble is drawn without looking. what is the probability of selecting a red or black marble?

An observer(o) spots a plane(p) taking off from a local airport and flying at a 29 degree angle horizontal to her line of sight and located directly above a tower(t). the observer also notices a bird circling directly above her. if the distance from the plane(p) to the tower(t) is 6,000ft., how far is the bird(b) from the plane(p).