A recent study at the North Pole suggests.that the batteries Santa puts in Lydia's favorite toy will last, on average, for 100 hours. The study also suggests the battery life is normally distributed with o = 7.3 hours. (a) Determine the probability that the battery in Lydia's toy will last at least 96 hours. (b) Determine the probability that Lydia will need new batteries before 72 hours have past