Answer:
$64.63
Explanation:
You want to know the total with tax of purchases of $28.61, 23.27, and 7.96 when they are subject to taxes of 5%, 0.5% and 2.5%.
Total sale
The sum of the individual prices is subject to tax that is the sum of the individual tax rates. The tax rate sum is ...
5% +0.5% +2.5% = 8%
Then the multiplier of the price is ...
total = subtotal × (1 +8%) = 1.08×subtotal
A calculator can do all the computations at once, so we don't actually need to know the subtotals in order to find the total sale amount.
(28.61 +23.27 +7.96) × 1.08 = 64.6272
The tax is generally rounded to the nearest cent, so ...
the total purchase price is $64.63.
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Additional comment
In the days before smart cash registers, the amount of sales tax was found by looking in a table supplied by the tax authority. It was always the same for any given purchase amount.
These days, the tax may be computed on the fly in such a way that the total tax collected is as near as possible to the total tax that needs to be collected.
That means a hundred instances of this purchase might have a total price of $64.63 for 72 of them, and $64.62 for the remaining 28 of them. That way, the total of the 100 sales would be $6462.72 and exactly the right amount of tax will have been collected. (At least one pizza chain collects tax this way.)