Before the development of new fracking technology, the opportunity cost of producing oil in the United States was the world market price. After the development of new fracking technology, the opportunity cost of producing oil in the United States is the world market price.

Side bar toggle icon performance in last 10 qs hard easy performance in last 10 questions - there are '3' correct answers, '3' wrong answers, '0' skipped answers, '1' partially correct answers about this question question difficulty difficulty 60% 42.2% students got it correct study this topic • demonstrate an understanding of sampling distributions question number q 3.8: choose the correct estimate for the standard error using the 95% rule.

Employees at a library check out books to patrons. books have an isbn and a name. the library sometimes has multiple copies of the same book. books have one or more authors. a patron is an individual who has an active (non-expired) library card. for each library card, we store the person's first and last names and their address. for each employee, we store their employee id, current salary, first and last name and their address. we also store the employee id of their current manager. each time we check out a book to a patron we need to store the date of the transaction, the employee who checked out the book to the patron, and the library card of the patron. some employees have library cards. if an employee patron turns in a book late, the fine that they pay is a percentage of their salary. some employees are authors who have library cards—they are allowed to check out as many books as they like.

Alarge tank is filled to capacity with 500 gallons of pure water. brine containing 2 pounds of salt per gallon is pumped into the tank at a rate of 5 gal/min. the well-mixed solution is pumped out at the same rate. find the number a(t) of pounds of salt in the tank at time t.