Euro zone business activity unexpectedly grew at a faster pace in October as companies received new orders at the quickest rate in 2-1/2 years, suggesting the bloc's economy gained momentum at the start of the final quarter, a survey showed on Friday. The HCOB Flash Eurozone Composite PMI, compiled by S&P Global, rose to 52.2 in October from 51.2 in September, marking the tenth consecutive month of expansion and reaching a 17-month high and confounding expectations in a Reuters poll for a dip to 51.0. PMI readings above 50.0 indicate growth in activity.