A parcel of air is at 20 and has a saturation vapor pressure at 24 mb If the water vapor content actually exerts a vapor pressure of only 12mb in 20 air the relative is What would the ap?

To calculate the relative humidity, you can use the formula:

[ \text{Relative Humidity} = \left( \frac{\text{Actual Vapor Pressure}}{\text{Saturation Vapor Pressure}} \right) \times 100 ]

In this case, the actual vapor pressure is 12 mb, and the saturation vapor pressure is 24 mb. Thus, the relative humidity is:

[ \text{Relative Humidity} = \left( \frac{12 \text{ mb}}{24 \text{ mb}} \right) \times 100 = 50% ]

Therefore, the relative humidity of the air parcel is 50%.