To solve the inequality \(2\sqrt{n} < 5\), we first divide both sides by 2:
\[ \sqrt{n} < \frac{5}{2} \]
Next, we square both sides to eliminate the square root:
\[ n < \left(\frac{5}{2}\right)^2 \]
Calculating \(\left(\frac{5}{2}\right)^2\):
\[ \left(\frac{5}{2}\right)^2 = \frac{25}{4} = 6.25 \]
This means that \(n\) must be less than 6.25.
Now, let's evaluate the provided options to see which values of \(n\) satisfy \(n < 6.25\):
- 12.5: \(12.5 \not< 6.25\)
- 8: \(8 \not< 6.25\)
- 16: \(16 \not< 6.25\)
- 18: \(18 \not< 6.25\)
None of the given options satisfy the inequality \(n < 6.25\). Therefore, there are no valid values for \(n\) among the provided responses.