Is -1/2 a natural ,whole , rational, or irrational number

Assume that the weights of quarters are normally distributed with a mean of 5.67 g and a standard deviation 0.070 g. a vending machine will only accept coins weighing between 5.48 g and 5.82 g. what percentage of legal quarters will be rejected? round your answer to two decimal places.

Math it's appreciated. (picture provided)

One hectometer is a) 1/1000 of a meter. b) 1/100 of a meter. c) 10 meters. d) 100 meters. e) 1000 meters.