Calculating the pH of a HCl-NaOH Mixture

[geffman1]

A solution which is formed by combining 200. mL of 0.15 M HCl with 300. mL of 0.090 M NaOH has a pH of ____

ive worked out concentration of H ion is 0.03 and the concentration of OH ions 0.027. but i don't know what to next?

answer is 2.2 thanks

 

[chemisttree]

Hmmmm. pH = -log[H+]

 

[Borek]

very similar pH calculation question