The woman sweeping floors at the McDonald’s on 204th Street had gray hair tracing her temples, and her colleague at the register looked to be at least 50. Down at the Micky-Ds on Fordham Road, the woman making french fries could have been a grandmother, and she was not the oldest one behind the counter. At the restaurant on East 170th, the employee on break had a wrinkled face; those on duty were younger, but few could pass for 30. The man taking orders on East 167th Street looked to be pushing 50. On Jerome Avenue, the entire staff—at the registers and the grill—seemed to be beyond their 20s.If there’s a typical teenage job in America, its pushing Happy Meals and Big Macs under the golden arches.