### Current

Let the current $I$ come out from the sphere $R_1$. At the surface of the sphere $I=\oint_S \mathbf{J}\cdot \mathbf{dS}=\oint_S (1/\rho)\mathbf{E}\cdot \mathbf{dS}=(1/\rho)\cdot 4\pi k q_1$.
Since the other sphere is far away, the potential of sphere $R_1$ can be found as $\phi_1=k q_1/R_1=I\rho /4\pi R_1$. The potential of the second sphere will be $\phi_2=-I\rho/4\pi R_2$, so that the potential difference $V=I(\rho/4\pi)(1/R_1+1/R_2)$ and the resistance $R=V/I=(\rho/4\pi)(1/R_1+1/R_2)$.