To convert the airplane's speed from kilometers per hour (km/h) to miles per hour (mph), you can use the conversion ratio:
1 kilometer ≈ 0.62 miles.
Given the airplane travels about 900 kilometers per hour, the conversion to miles per hour is as follows:
\[ 900 , \text{km/h} \times 0.62 , \text{miles/km} = 558 , \text{mph} \]
Thus, the airplane's speed in miles per hour is:
558 mph.
The correct response is 558.