CHEM HELP PLEASE. A student is titrating 25.0 mL of a solution of NaOH with a 0.247M HCL solution. Accidently,?

A student is titrating 25.0 mL of a solution of NaOH with a 0.247M HCl solution. Accidently, the student adds too much HCl. The amount of HCl added is 34.38mL. Using a buret filled with the unknown NaOH solution, the student finds that addition of 4.77mL of the base reaches the endpoint. What is the concentration of the NaOH?