Which expression is equivalent to 45a-10b A: 5(9a-10b)

B: 45(a-10b)

C: 5(9a+2b)

D: 5(9a-2b)

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?