A union of restaurant and foodservice workers would like to estimate the mean hourly wage,

, of foodservice workers in the U.S. The union will choose a random sample of wages and then estimate using the mean of the sample. What is the minimum sample size needed in order for the union to be 95% confident that its estimate is within $0.40 of ? Suppose that the standard deviation of wages of foodservice workers in the U.S. is about $2.25. Carry your intermediate computations to at least three decimal places. Write your answer as a whole number (and make sure that it is the minimum whole number that satisfies the requirements).