10 books are placed at random in a shelf. The probability that a pair of books will always be together is -
A. $$\frac{{1}}{{10}}$$
B. $$\frac{{9}}{{10}}$$
C. $$\frac{{1}}{{5}}$$
D. $$\frac{{3}}{{10}}$$
Answer: Option C
Solution(By Examveda Team)
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 = $$\frac{{1}}{{5}}$$
This Question Belongs to Arithmetic Ability >> Probability
Related Questions on Probability
A. $$\frac{{1}}{{2}}$$
B. $$\frac{{2}}{{5}}$$
C. $$\frac{{8}}{{15}}$$
D. $$\frac{{9}}{{20}}$$
A. $$\frac{{10}}{{21}}$$
B. $$\frac{{11}}{{21}}$$
C. $$\frac{{2}}{{7}}$$
D. $$\frac{{5}}{{7}}$$
A. $$\frac{{1}}{{3}}$$
B. $$\frac{{3}}{{4}}$$
C. $$\frac{{7}}{{19}}$$
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What is the probability of getting a sum 9 from two throws of a dice?
A. $$\frac{{1}}{{6}}$$
B. $$\frac{{1}}{{8}}$$
C. $$\frac{{1}}{{9}}$$
D. $$\frac{{1}}{{12}}$$
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