You would subtract the tax first which 62.99-2.99=60$. Then you would divide the $60 left by 6 and 60 divided by 6 equals 10 so each shirt costs $10.
8 turnips + 6 turnips = 14 turnips together
The value would be 28,000*(1-0.0725)*(1-0.0725)*(1-0.0725)*(1-0.0725)*(1-0.0725)
which is 28,000*0,9275

which equals 28,000*0.6863=$19,219
You can use the change of base formula to get

and also

In general, the change of base formula is
