PLZ can any one give me answer ASAP :D?

A beaker with 200 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 0.100M . A student adds 5.90 ml of a 0.450M HCL solution to the beaker. How much will the pH change? The pka of acetic acid is 4.760.