Let the taxable value of the Walky-Talky set be Rs x.
Rate of GST = 12% (Given)
Taxable value of the Walky-Talky set + Amount of GST = Rs 84,000
= Rs 75,000
So, the taxable value of the Walky-Talky set is Rs 75,000.
Now, Rate of CGST = Rate of SGST = 6%
∴ Amount of CGST on the Walky-Talky set = Amount of SGST on the Walky-Talky set = 6% of Rs 75,000 = = Rs 4,500
Thus, the amount of CGST charged by the dealer is Rs 4,500 and the amount of SGST charged is Rs 4,500.