Why does tax get calculated cents per dollar and not a set amount?

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10

Type the correct answer in the box. use numerals instead of words. if necessary, use / for the fraction bar.

According to a study conducted in 2015, 18% of shoppers said that they prefer to buy generic instead of name-brand products. suppose that in a recent sample of 1500 shoppers, 315 stated that they prefer to buy generic instead of name-brand products. at a 5% significance level, can you conclude that the proportion of all shoppers who currently prefer to buy generic instead of name-brand products is higher than .18? use both the p-value and the critical-value approaches.