Sаm оwns а cаndy factоry and hires wоrkers in a competitive labor market to pack cases of candy. The company's weekly output of cases of candy varies with the number of workers hired, as shown in the accompanying table. If each case sells for $10 more than the cost of the materials used in producing it, and the competitive market wage is $1,350/week, then how many workers should Sam hire each week?