A supermarket chain has developed a weight-loss plan. Everyday, dieters on this plan pick package of freshly prepared meals for the whole day. The plan lasts 4 weeks, but there are no commitments and dieters buy packages on a day-by-day basis. On any given day, there are an average of 60,000 active dieters in the plan. The chain sells on the average 3,750 packages everyday to dieters starting on the plan. Most dieters quit before the end of the plan. It is estimated that only 20% of the dieters starting the plan follow it until completion. (The proportion of dieters staying on the plan more than 4 weeks is negligible.) a. How many of the active dieters on any given day will follow the plan to completion? b. On average, how many days do quitting dieters stay on the plan?