Let the taxable value of the toy car be Rs x.
Rate of GST = 18% (Given)
Taxable value of the toy car + Amount of GST = Rs 1770.
∴x+18100x=1770
⇒118100x=1770
⇒x=100118×1770=1500
So, the taxable value of the toy-car is Rs 1,500.
Now,
Rate of CGST = Rate of SGST = 9%.
∴ Amount of CGST on the toy-car = Amount of SGST on the toy-car
= 9100×1500=135 Rs.