A furniture manufacturing company produces tables and chairs, which sell at $2000 and $3000 per unit, respectively. The daily production time is 10 hours, and the budget to buy supplies and materials is $1200. Also, the total number of units of each type cannot exceed 4. Each table requires 2 hours of production and 3 hours for each chair. The supply and material costs are $400 for tables and $200 for chairs.

a) How many tables and chairs should be produced daily to maximize revenue?

b) Would be any additional profit if the company would increase the workday to 12 hours?