An electric field of magnitude e is measured at a distance r from a point charge q. if the charge is doubled to 2q, and the electric field is now measured at a distance of 2r from the charge, what is the value of the new electric field?

Electric field is proportional to the charge and inversely proportional to the square of distance:

With charge 2q and distance 2r, the electric field is proportional to:

The new electric field is half of that of the original measured field.