An environmental agency worries that many cars may be violating clean air emissions standards. The agency hopes to check a sample of vehicles in order to estimate that percentage with a marg of error of 4% and 99% confidence. To gauge the size of the problem, the agency first picks 40 cars and finds 10 with faulty emissions systems. How many should be sampled for a full investigatio The environmental agency should sample at least (Round up to the nearest whole number.) vehicles.