An item costs $ 390 before tax, and the sales tax is $31.20 . Find the sales tax rate. Write your answer as a percentage.

Step-by-step explanation:

390x=31.20

divide each side by 390

you get 0.08

multiply that by 100

you get 8%

12.4%

Step-by-step explanation:

The results from the random sample counts 124 from a total of 1000 people that wear contact lenses. This means is the percentageof the people in the sample that wear contact lenses.Because it is a random sample, it is suppose to reflect the behavior of the total population. Then we can expect or predict  similar percentage of Americans wearing contact lenses (12.4%).