3. Consider an economy divided into an agricultural sector (A) and an industrial sector (I). To produce one unit in sector A requires 1/6 unit from A and 1/4 unit from I. To produce one unit in sector I requires 1/4 unit from A and 1/4 unit from I. Suppose external demands (demands from general population) in each of the two sectors are 60 units.

Find the number of units that have to be produced in each sector in order to meet the demands.