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Q4. A post office is planning to build mail boxes along a wall in the mail room that is 1.8 metres high and 12 metres wide. The boxes come in two sizes: large boxes are 25cm wide and 15cm high; small boxes are 12cm wide and 10cm high. To simplify the design of the space, it has been decided that columns will contain exclusively large boxes or exclusively small boxes (i.e, no column will contain a mixture of large and small boxes). Post office officials have determined that at least half the available space should contain large boxes. Determine the design in order to have the maximum number of boxes. Just build the LP program - not need to figure out the optimal values. (9 points)