Suppose that the lifetimes of lightbulbs are approximately normally distributed with a mean of 56 hours in a standard deviation of 3.2 hours with this information answer the following questions A. what proportion of lightbulbs will last more than 60 hours b. what proportion of lightbulbs will ask 52 hours or less C. what proportion of light bulbs will last between 58 and 61 hours D what is the probability that a randomly selected lightbulbs last less than 46 hours