Final answer:
The cruising speed of the airplane is 6.25 km/min.
Step-by-step explanation:
To find the cruising speed of the airplane, we first need to determine the distance it travels in 1/12 of a minute. We can calculate this by multiplying the cruising time (1/12 minute) by the speed:
Distance = Speed × Time
Distance = 1 km × (1/12 min) = 1/12 km = 0.0833 km
Therefore, the cruising speed of the airplane is 0.0833 km per 1/12 minute, or 6.25 km/min.