I  took a picture of the table so it would be easier for you to answer.
The questions are:
a) what load would give an extension of 30mm?
b) what would be the length of the spring if the load was 4.5N ?
c) the elastic limit of a spring is the point at which it no longer stretches evenly and is permanently deformer even when the load is removed. at what load is the elastic limit of the spring reached?

http://fr.tinypic.com/view.php?pic=2mnqb11&s=3

help would be very much appreciated thanks!