1- Battery manufacturers compete on the basis of the amount of time their products last in camerasand toys. A manufacturer of alkaline batteries has observed that its batteries last for an averageof 6.9 hours when used in a toy racing car. The amount of time is normally distributed with astandard deviation of 2.1 hours. a. What is the probability that the battery lasts between 6 and 8 hours? b. What is the probability that the battery lasts longer than 7 hours? c. What is the probability that the battery lasts less than 4 hours? d. What is the amount of time below which only 10% of all a battery lasts?