For the Item that costs $64 before tax the sales tax is $6
Hence for the item that costs $1 before tax the sales tax is $(6/64), by the rule of proportions or unitary method
Hence for the item that costs $100 before tax the sales tax is $[100*(6/64)], by the rule of proportions
which is = $75/8 or $9.45
Therefore, the item having a Sales tax of $9.45 or $75/8 costs $100 before tax
thus the item having a Sales tax of $1 costs $[(100*8)/75] before tax, by the rule of proportions or unitary method
thus the item having a Sales tax of $8.25 costs $[(100*8*8.25)/75] before tax, by the rule of proportions
which is = $88
