20) the first term in an arithmetic sequence is -1. the fourth term in the sequence is -4. the tenth term in the sequence is -10. which function can be used to find the nth term of the arithmetic sequence?

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?