an airplane is flying 800 meters in the air. it starts decending at a rate of 30 meters per second. if x represents the total number of seconds the plane decends, which equation can be used to represent the planes desent

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?