the amount of time a certain brand of light bulb lasts is normally distribued with a
mean of 1600 hours and a standard deviation of 55 hours. using the empirical rule,
what percentage of light bulbs last between 1490 hours and 1710 hours?

Barney & noblet customers can choose to purchase a membership for $25 per year members receive 10% off all store purchases 1. how much would a member pay per year if he bought $50 worth of items each year? 2. write a slope-intercept equation that expresses how much a member pays per year using x to represent his purchases per year 3. how much would a member have to spend per year to pay off his membership fee?