When you add HCl NaOH you get this reaction:
H OH- -> H20
The number of moles of H is 1*0.03 = 0.03 mol
The number of moles of OH- is 1*0.025 = 0.025 mol
This means after everything has reacted you have 0 moles of OH- and 0.03-0.025 = 0.005 mol.
So pH = -log(0.005/0.055) = 1.05
KW it's not needed here.