Tammy attends tap and ballet classes at her dance studio. Each tap class is 90 minutes long and each ballet class is 60 minutes long. A tap class costs $17 and a ballet class costs $15. Last week, Tammy paid $49 for 240 minutes of dance classes. Which system of equations can be used to determine the number of tap classes, x, and the number of ballet classes, y, that Tammy took last week?

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.