a major cell phone service provider has determined that the number of minutes that its customers use their phone per month is normally distributed with a mean equal to 455.5 minutes with a standard deviation equal to 177.8 minutes. as a promotion, the company plans to hold a drawing to give away one free vacation to hawaii for a customer who uses between 400 and 402 minutes during a particular month. based on the information provided, what proportion of the company's customers would be eligible for the drawing?