LC circuit, resonant frequency
I solved the first equation and came up with 86.866 nH @ 25 pF for L.

For the second equation I used; $$C = \frac{1}{L\cdot(F^2)\cdot(pi^2)\cdot 4}$$ = 37.649 pF.

The final answer is 12.------. Sorry, but you need to solve the last digits yourself so you understand the math. If you plan this as a career, it pays to build up a library or cheat-sheet of these resonance equations. There are a lot of them.