Let the number of toys produced be x.
∴ Cost of production of each toy =Rs(55−x)
It is given that, total production of the toys = Rs750
∴x(55−x)=750
⇒x2−55x+750=0
⇒x2−25x−30x+750=0
⇒x(x−25)−30(x−25)=0
⇒(x−25)(x−30)=0
Either, x−25=0orx−30=0
⇒x=25 or x=30
Hence, the number of toys will be either 25 or 30.