Hint 8

The equinoxes are when the Sun lies in the plane of the Earth's equator, which occurs at points $180^\circ$ apart on the Earth's orbit. You should consider the orbit as approximately circular, with the sun displaced by $\epsilon a$ from the centre. You want to find that the difference between the areas of the segments of the ellipse on either side of the line through the equinoxes, so that you can use Kepler's Second Law to get the corresponding time difference. Sketch the orbit and show that the difference between the segments is approximately given by a rectangle length $2a$ and width $2a\epsilon$. Hence the area difference is approximately $4a^2\epsilon$ which gives a time difference of about 7 or 8 days.