Concept:Set up equations from the two selling conditions using cost prices of the laptop and printer.Explanation:Let the cost price of the laptop be x and the cost price of the colour printer be y.In the first case, there is no overall loss or gain.Loss on laptop =12.5% of x=81​xGain on printer =25% of y=41​ySo, 81​x=41​yThis gives x=2y.In the second case, there is a total loss of ₹1200.Gain on laptop =8% of x=0.08xLoss on printer =20% of y=0.20yNet loss is 0.20y−0.08x=1200.Substitute x=2y into the equation:0.20y−0.08(2y)=12000.20y−0.16y=12000.04y=1200y=₹30000Answer:He paid ₹30,000 for the colour printer.