Shawn and ellie are construction workers. shawn can complete a concrete job in 4 hours, while ellie can complete it in 6 hours. the foreman says that it will take them 5 hours to complete it if they work together. explain each step in solving this equation, and determine if the foreman is correct or not.

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.