A spherical hole of radius $\frac{\text{R}}{2}$ is drilled from a planet of mass M as shown in the figure. If the gravitational acceleration at a point on the surface of the planet just above the hole is $11/n \text{m}/{\text{s}}^2\text{,}$ find the value of n.[Given : $\text{G}=6.6\times {10}^{-11} {\text{N.m}}^2/{\text{kg}}^2,\text{R}=6\times {10}^6 \text{m},\text{M}=6\times {10}^{24} \text{kg}$ ]