\(\text { K.E. }=\frac{{n}^{2} {~h}^{2}}{8 \pi^{2} {mr}^{2}} \quad=\frac{4 {~h}^{2}}{8 \pi^{2} {~m}\left(4 {a}_{0}\right)^{2}}\)

\(\quad\quad\quad\quad\quad\quad\quad\quad=\left(\frac{4}{8 \pi^{2} \times 16}\right) \frac{{h}^{2}}{{ma}_{0}^{2}}\)

\(\Rightarrow {x}=315.507\)

\(\Rightarrow 10 {x}=3155 \text { (nearest integer) }\)