Rachel McCullough, who said she has worked at two different McDonald’s in the past few years, speaks during a protest Tuesday in support of higher wages for fast-food workers. The protest outside the McDonald’s on J.M. Keynes Drive in the University City area was part of a series of events planned Tuesday in about 30 cities, including Boston, Chicago, Los Angeles and Miami. Protesters sought to call attention to the denial of overtime pay and other violations they say deprive workers of the money they’re owed. McDonald’s has said it will investigate the allegations and take any necessary action.