A young couple, Maria and Helmut, want to divide their main household chores (cleaning, cooking, dish washing, laundry) between them so that each has two tasks but the total time they spend on household duties is kept to a minimum. Their efficiencies on these tasks differ, where the time each would need to perform each of the task is given in the following table:

	Time Needed
	Cleaning	Cooking	Dish Washing	Laundry
Maria	4.5	7.8	3.6	2.9
Helmut	4.9	7.2	4.3	3.1

1. Formulate a binary programming model for this problem. What are the decision variables, objective function and constraints?
2. Using Excel's Solver find and describe the optimal solution.