1.15 In December, General Motors produced 6,600 cus-tomized vans at its plant in Detroit. The labor productivity at this plant is known to have been 0.10 vans per labor-hour during that month. 300 laborers were employed at the plant that month. a) How many hours did the average laborer work that month? b) If productivity can be increased to 0.11 vans per labor-hour, how many hours would the average laborer work that month?