Abox in a college bookstore contain books and each book in the box is a history books, an english or a science book. if one third of these book are history books and one sixth are english book, what fraction of the book are science book

1. according to the internal revenue service, the mean tax refund for the year 2007 was $2,708. assume the standard deviation is $650 and that the amounts refunded follow a normal probability distribution. a. what percent of the refunds are more than $3,000? b. what percent of the refunds are more than $3,000 but less than $4,000? c. what percent of the refunds are less than $2,000?