Use correct units where appropriate (inches, years, etc). The axes of graphs should be drawn with a ruler or computer. Work will be graded for neatness, completeness and correctness. The lifetime of a certain kind of battery is exponentially distributed, with an average lifetime of 20 hours. 1. We are interested in the lifetime of one battery. Define the random variable X in words. 2. Give the distribution of X using numbers, letters and symbols as appropriate. X~ 3. Find the probability that the lifetime of one battery is between 20 and 25