Divide Sales Price by 200% (ie 2). So cost is half of sales price.
You have missing variables such as the critically important total sales.
72
34% discount
11.20
$3.30 and $15.00
The total price with tax is $215.79
$80.00
The total tax is $0.46 and the total price with tax is $9.21
1000x14%=140 add to the $1000 brings the price to $1140.00
The total tax is $4.83 and the total price with tax is $73.83
The total tax is $4.27 and the total price with tax is $65.27
The total tax is $3.57 and the total price with tax is $54.57
The total tax is $1.20 and the total price with tax is $21.20
The total tax is $9.66 and the total price with tax is $147.66
The total tax is $1.75 and the total price with tax is $26.75
The total tax is $0.60 and the total price with tax is $8.10