The time until first failure of a brand of ink jet printers is normally distributed with a mean of 1500 hours and a standard deviation of 160 hours. a large company buys 4 such printers. what is the probability that the mean lifetime of the 4 printers is more than 1568 hours?

What is a sort of auction for stocks in which traders verbally submit their offers?

Oz makes lion food out of giraffe and gazelle meat. giraffe meat has 18 grams of protein and 36 grams of fat per pound, while gazelle meat has 36 grams of protein and 18 grams of fat per pound. a batch of lion food must contain at least "46,800" grams of protein and 70,200 grams of fat. giraffe meat costs $1/pound and gazelle meat costs $2/pound. how many pounds of each should go into each batch of lion food in order to minimize costs? hint [see example 2.]

Firms like papa john’s, domino’s, and pizza hut sell pizza and other products that are differentiated in nature. while numerous pizza chains exist in most locations, the differentiated nature of these firms’ products permits them to charge prices above marginal cost. given these observations, is the pizza industry most likely a monopoly, perfectly competitive, monopolistically competitive, or an oligopoly industry?