(i) Let the number of toys produced on that day be x. Therefore, the cost of production (in rupees) of each toy that day = 55 - x So, the total cost of production (in rupees) that day = x(55 - x) Therefore, x(55 - x) = 750 i.e., 55x - x^2 = 750 i.e., -x^2 + 55x - 750 = 0 i.e., x^2 - 55x + 750 = 0 Therefore, the number of toys produced that day satisfies the quadratic equation x^2 - 55x + 750 = 0 which is the required representation of the problem mathematically.