This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
Let the number of toys produced in a day = x
Cost of each toy = Rs(55-x)
Total cost = No.of toys × cost of each toy
                 = x × (55-x)
                 = 55x - x²

given that 55x - x² = 750
⇒x²-55x+750=0   (required quadratic equation)

Is my answer matching with what you had expected? If you take cost of each toy as variable, you will get a different answer and both answers are correct,