Seven different books (A, B, C, D,E,F,G and H) are to be arranged on a shelf. Books A and B are to be arranged first and second starting from the right of the shelf. The number of different orders in which books C, D,E,F and G may be arranged is
Choose one:
A) 9!  B) 12!  C) 5!  D) 25!  E) 18!
Solution   Since books A and B are arranged first and second, only books C,D,E,F and G will change order. Therefore it an arrangement problem involving 5 items and the number of different order is given by   5!   Answer 5!
<result>C</result>
Seven different books (A, B, C, D,E,F,G and H) are to be arranged on a shelf. Books A and B are to be arranged first and second starting from the right of the shelf. The number of different orders in which books C, D,E,F and G may be arranged is