We are told that a 7% tax is applied to the original sales price, in order to determine the tax amount we just have to multiply the original price ($46.85) by the tax percentage (0.07 as 7% in decimal form), then we get:
Tax amount = 0.07×46.85 ≈ 3.28
By adding the tax amount to the original price we should get the final price, like this:
Total purchase price = 46.85 + 3.28 = 50.13
Then, the total purchase price after tax is $50.13
