Let the merchant stock x desktop models and y portable models. Therefore, x≥0 and y≥0 The cost of a desktop model is Rs 25000 and of a portable model is Rs 4000 . However, the merchant can invest a maximum of Rs 70 lakhs.∴25000x+40000y≤7000000 5x+8y≤1400 The monthly demand of computers will not exceed 250 units.∴x+y≤250 The profit on a desktop model is Rs 4500 and the profit on a portable model is Rs 5000 .Total profit, z = 4500x + 5000yThus, the mathematical formulation of the given problem isMaximum Z=4500 x+5000 ysubject to the constraints,5x+8y≤1400 x+y≤250 x,y≥0 The feasible region determined by the system of constraints is as follows.The corner points are A(250,0), B(200,50), and C(0,175). The values of Z at these corner points are as follows.The maximum value of Z is 1150000 at (200,50).Thus, the merchant should stock 200 desktop models and 50 portable models to get the maximum profit of Rs 1150000 .