Four books are arranged on a book shelf. The positions of the books are numbered 1 through 4, from left to right. For each of the following pairs of conditions, count the number of orderings possible.
- This is only a practice test, it is designed to help you revise your concepts
- The test contains questions, only 1 option is correct for each question
- This is a timed test.
- After you have finished the test, press on the 'Finish Test' button to know your score and get the correct answers