With the wind, a jet can fly 2500 km in 2 hours 30 minutes. against the wind, it can fly only 2000 km in the same amount of time. find the rate of the jet in still air and the rate of the wind.

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.