311. Using the available references, if the dry bulb temperature is 84°F and the wet bulb temperature is 81°F, what is the relative humidity in a cargo hold?

The relative humidity is 88%, determined by plotting the dry bulb (84F) and wet bulb (81F) temperatures on a psychrometric chart and reading the nearest relative humidity curve. A small wet-bulb depression (3F) indicates high humidity, consistent with a reading near 88%.