A machine shop produces heavy duty high endurance 20-inch rods that are meant for use in a variety of military grade equipment.
On occasion, the machine malfunctions and produces a groove or a chisel cut mark somewhere on the rod. If such defective rods can be cut so that there is at least 15 consecutive inches without a groove, then the rods can be salvaged for other purposes. If the location of the groove on a rod is described by a uniform distribution, what is the probability that a defective rod can be salvaged?