An item costs $320 before tax, and the sales tax is $12.80. Find the sales tax rate. Write your answer as a percentage

4%

Step-by-step explanation:

As, some rate of $320 will give u 12.80

Now to find the percentage u always use this procedure :

Sales tax value = 12.80 divided by the the total cost ( $320) multipled by hundred

So 12.80/320 x 100 = 4

So 4%

This method help me alot in my solving skills

And used it everytime a question like this is given

So I hope u use it for such questions and u will get right with all hope!

Hope this helps!!

step-by-step explanation:

part a. the differences are decreasing, so we know the sequence is not arithmetic. the ratios are constant (=3/4), so we know the sequence is geometric.

part b. from part a, we know the common ratio is 3/4, so each term is 3/4 of the one before. the initial term is the number of gallons at h=1.

g[h] = (3/4)·g[h-1]

g[1] = 384 . . . . initial value required for a recursive definition

part c. the general formula for a geometric sequence is

a[n] = a[1]·r^(n-1)

we have a[1] = 384, r = 3/4, and the term number given by h. the formula that follows is

g[h] = 384·(3/4)^(h-1)

part d. filling in the value and doing the arithmetic, we have

g[12] = 384·(3/4)^11 ≈ 384·0.042235136 ≈ 16.2183 . . gallons

part e. each gallon is 4 quarts, so

16.2183 gal × 4 qt/gal = 64.8732 qt