How far apart would two index contours be on a map with a contour interval of 5 meters?

Most likely with a contour interval of 5 meters, index contours would be every 4 contour lines or say 0, 20, 40, 60, 80 and 100 I would say and these intervals would be in bold compared to the intervening contour lines and would help in calculating the elevation of a particular point.

Asmall closed hole formed in an outwash plain or moraine. forms when a  glacier retreats then remains stationary. 

Terrestrial planets will likely be located nearer the planetary systems star than any jovian planets