Ithink ik the answer but i want to make sure it’s correct

To solve this problem, we must first find the tax Mr. Harty owes for his shirt, and then add this to the preexisting total of the shirt.

To find the amount of tax Mr. Harty has to pay, we must find 6% of 20. First, we must convert 6% to a decimal, by dividing 6/100. The reason we do this is because percentages are parts of a total 100%, so the fraction must be the part (6) over the whole (100). Because 6/100 = 0.06 and "of" refers to multiplication in math, we can set up the following expression to find the tax:

6% of $20

0.06 * ($20)

0.06(20)

To simplify this expression, we simply multiply the two numbers together, which gives you 1.2. This means that Mr. Harty's tax amount was $1.20, so we must add this to the cost of his shirt ($20).

$20 + $1.20 = $21.20

Therefore, your answer is C)$21.20.

Hope this helps!