Adding a strong acid to a buffer?

A beaker with 175 mL of an acetic acid buffer with a pH of 5.00 is sitting on a benchtop. The total molarity of acid and conjugate base in this buffer is 0.1 M. A student adds 9.00 mL of a 0.410 \it M \rm HCl solution to the beaker. How much will the pH change? The pKa of acetic acid is 4.76.