phy mc electric

Since resistance R = r.L/A
where r is the resistivity of copper
L is the length of wire
A is the cross-sectional area

and mass m = d.(AL), d is the density of copper
i.e. A = m/d.L

hence, R = r.L(d.L/m) = r.d.L^2/m
that is, given r, d and L are constants, resistance R is inversely proportional to m

R(A)/R(B) = mass(B)/mass(A) = 9/4