There is a sales tax $6 on an item that costs $80 before tax. The sales tax on a second item is $11.25. How much does the second item cost before tax?

The answer to this question would be: $138.75

In this question, for item with $80 total price the tax is $6 which mean the actual price (before tax) is $80-$6 = $74.

That mean the ratio of the tax: item = 6:74

Then for the second item, if the tax is $11.25 then the price before tax would be: $11.25 * 74/6 = $138.75

The discount is 6:80 = 7.5%

the second item's price before tax is 11.25:7.5% = (11.25 x 100) : 7.5 = 150

the answer is $150