Under what condition are pressure altitude and density altitude the same?

Pressure altitude and density altitude are the same when the atmospheric conditions match those of standard atmosphere, which occurs at standard temperature. Pressure altitude is derived from the altimeter setting adjusted to standard atmospheric pressure (29.92 inches of mercury), while density altitude accounts for changes in temperature, pressure, and humidity.

When the temperature is exactly at the standard value, the air density will be consistent with the pressure as measured at sea level. Under these conditions, the pressure altitude and density altitude will converge and be equal. If the temperature is higher or lower than standard, it impacts the density of the air, causing the two altitudes to differ.

Thus, encountering this scenario at standard temperature leads to equal measurements of both pressure and density altitude, making this the correct response.