1. An important bolt is manufactured for use in high speed trains at a plant in Germany.  The lengths of the manufactured bolts are normally distributed with a mean of 20.0 cm and a standard deviation of 0.042 cm.  Because of variation due to operator error and other more subtle issues, some bolts are made too short and others are too long to be used safely.  Bolts that come off the production line shorter than 19.88 cm or longer than 20.12 cm cannot be used.  What percentage of bolts will be unusable?