A ballon is stuck In a tree 70 feet above sea level . Directly above the ballon , an airplane is flying 83 feet above sea level . Directly below the airplane is a shark swimming 10 feet below sea level. (i’m really confused and i need help )

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?