All matter is composed of atoms, indestructible building blocks.
Humans rely on photosynthesis to generate food as well as provide energy for heating, lighting, and electricity.
Distance = speed X time
In this example, the speed of the airplane = 840km. The time (that the question is asking)is how far can it travel in 1 hour.
So just plug in your numbers.
Distance = 840km X 1 hour = 840km/hour or 840km for short.
