In mathematics, a percentage is a number or ratio expressed as a fraction of 100.
Answer:

Explanation:
We are given that
Diameter=d=
Thickness=
Radius=
Using 
Dielectric constant=8
Resistance =
Internal specific resistance=r=100 ohm cm=
Using 1 m=100 cm
Internal resistance per unit length=
Using 
Internal resistance per unit length=
The text does not specify whether the resistance R of the wire must be kept the same or not: here I assume R must be kept the same.
The relationship between the resistance and the resistivity of a wire is

where

is the resistivity
A is the cross-sectional area
R is the resistance
L is the wire length
the cross-sectional area is given by

where r is the radius of the wire. Substituting in the previous equation ,we find

For the new wire, the length L is kept the same (L'=L) while the radius is doubled (r'=2r), so the new resistivity is

Therefore, the new resistivity must be 4 times the original one.
To answer these questions just use the equations for potential energy using the mass and heights described. the potential energy at the prescribed heights = the initial kinetic energy required to reach that height.
Make sure you calculate the force of gravity on the surface using the radius of the planet.