Red Seal Plumbing Practice Exam

This is because the decrease in input rating for every thousand feet above 4500 feet above sea level is directly proportional to the decrease in air density at higher altitudes. This means that the higher the altitude, the lower the air density, resulting in a lower input rating for the appliance. Therefore, the higher the altitude, the greater the decrease in input rating. Answer options A, C, and D are incorrect because they do not take into account the direct relationship between altitude and air density. They also do not accurately reflect the rate of decrease in input rating at higher altitudes. Additionally, answer option A represents a decrease of only 2%, which may not be significant enough to impact the performance of the appliance. Answer option D represents a decrease of 8%, which may be too high for most appliances. Therefore, answer option B, representing a decrease of 4%, is the best and