in denver, 120 people are willing to work an hour as hostesses if the wage is $20 per hour. for each additional $5 that the wage rises above $20, an additional 30 people are willing to work an hour. for wages of $20, $25, $30, $35, and $40 per hour, plot the daily labor supply curve for hostesses on the following graph. supply 0 30 60 90 120 150 180 210 240 270 300 50 45 40 35 30 25 20 15 10 5 0 wage rate (dollars per hour) quantity of labor (number of workers) what is one explanation for why this labor supply curve is upward sloping? the opportunity cost of leisure increases as wages increase. unemployment benefits are steadily declining. people prefer to spend time doing leisure activities rather than working. labor production functions exhibit diminishing marginal returns.