10 books are placed at random in a shelf. The probability that a pair of books will always be together is ?	Choose one:
A) 1/9
B) 1/6
C) 1/5
D) 1/0
E) 1/1
10 books can be rearranged in 10! ways consider the two books taken as a pair then number of favourable ways of getting these two books together is 9! 2!   Required probability = 1/5   Answer: 1/5
<result>C</result>
10 books are placed at random in a shelf. The probability that a pair of books will always be together is ?