According to Kepler's second law.
The planets move in an elliptical orbit. An elliptical orbit is non-circular which means its radius is not uniform as Sun is present in one of the foci.
According to Kepler's law
Areal speed is constant. This means that when the planet is near the sun, its speed increases and when it is farther from the sun its speed decreases.
When speed is more, the time taken is less and when the speed is less, the time taken will be more.
Thus, areal speed always remains constant.
