At a blood drive, 6 donors with type O + blood, 3 donors with type A+ blood, and donors with type B+ blood are in line. In how many distinguishable ways can the donors be in line? The donors can be in line in nothing different ways.

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?