Final answer:
Water boils at a temperature lower than 100°C at an altitude of 1500 m with an atmospheric pressure of 4/5 atm. The exact value cannot be calculated from the information provided, but it will be less than the boiling point at sea level.
Step-by-step explanation:
The boiling point of water decreases as altitude increases because atmospheric pressure is lower at higher altitudes, decreasing the pressure exerted on the water surface. At sea level, where atmospheric pressure is 1 atm, the boiling point of water is 100°C. However, as you ascend to altitudes such as 1500 m or about 5000 ft, the atmospheric pressure decreases, resulting in a lower boiling point for water.
Given that atmospheric pressure at 1500 m is 4/5 atm, we can use boiling point elevation and depression concepts to find the approximate boiling point of water at this altitude. Unfortunately, an exact formula or table isn't provided within the context of the question, so we can't calculate an exact boiling point value here. However, we can safely say the boiling point would be lower than 100°C, which applies at standard atmospheric pressure (1 atm).
For example, in Denver, Colorado, which is at an altitude approximately 1600 m above sea level, the atmospheric pressure is around 640 mmHg, and water boils at approximately 95°C. The answer would be somewhat lower still for 1500 m altitude if the pressure is 4/5 atm.