Question

KLEERCO supplies under-hood emission-control air pumps to the automotive industry. The pump is vacuum powered and works while the engine is operating. It cleans the exhaust by pumping extra oxygen into the exhaust system. If a pump fails before the vehicle reaches 50,000 miles, Federal emission regulations require that it be replaced at no cost to the vehicle owner. The company's current air pump lasts an average of 61,000 miles with a standard deviation of 9,000 miles. The number of miles a pump operates before being ineffective has been found to obey a Normal distribution.

What percentage of the company's pumps will fail at mileage between 42,000 and 57,000? [please round the answer up to 1 decimal]

Answer 1