Hi :D
First, you have to calculate the concentration of the HCl and NaOH solutions using their pH values.
pH = -log[H+] ;
[H+] = 10^(-pH) ;
[H+] = 10^(-2.50).
For the NaOH solution : pH = 14 - pOH.
Since you're mixing equal volumes of HCl and NaOH, and their concentrations are the same, they will neutralize each other completely.
Now, calculate the concentration of H+ and OH- in the resulting solution after neutralization.
Then, you can calculate the pH of the resulting solution using the concentration of H+.
I'll let you try, and ask the question again if needed. :)
See you soon :D