Ahiker walks up and down a hill. the hill’s cross section can be modeled by the function y = – 3/4|x – 300| + 400 where x and y are measured in feet and d: [0, 600]. how far does the hiker walk?

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?