A Bright Idea. A company produces lightbulbs whose life follows the N(1500; 300) distribution, i.e. the lifetimes of lightbulbs have a normal distribution with a mean of 1500 hours and a standard deviation of 300 hours. Use this information to answer the following questions. (a) Find the probability that a lightbulb burns out before 1050 hours of use. (b) Find the proportion of lightbulbs that will last longer than 1650 hours (c) What is the probability that a bulb's lifetime will be between 1140 and 1620 hours? (d) Only 5% of the bulbs last longer than how many hours? (e) The middle 50% of bulbs last between how many hours?