Hank's speedometer reads 60 miles per hour, but during a road test he finds that he was actually driving 56 miles per hour. What is the percent error in Hank's speedometer? Round to the nearest tenth. Show your work.

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?