A Company's Manufacturing Process Uses 500 Gallons of Water at a Time.A

Multiple Choice

A company's manufacturing process uses 500 gallons of water at a time.A "scrubbing" machine then removes most of a chemical pollutant before pumping the water into a nearby lake.To meet federal regulations the treated water must not contain more than 80 parts per million (ppm) of the chemical.Because a fine is charged if regulations are not met, the company sets the machine to attain an average of 75 ppm in the treated water.The machine's output can be described by a normal model with standard deviation 4.2 ppm.What percent of the batches of water discharged exceed the 80 ppm standard?

A) 11.7%
B) 1.17%
C) 88.3%
D) 8.83%
E) 3.89%