Last year, the numbers of skateboards produced per day at a certain factory were normally distributed with a mean of 20,500 skateboards and a standard deviation of 55 skateboards.(
a. on what percent of the days last year did the factory produce 20,555 skateboards or fewer? (
b. on what percent of the days last year did the factory produce 20,610 skateboards or more? (
c. on what percent of the days last year did the factory produce 20,445 skateboards or fewer?