10 books are placed at random in a shelf. The probability that a pair of books will always be together is -

Tickets numbered 1 to 20 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn has a number which is a multiple of 3 or 5?

A. $$\frac{{1}}{{2}}$$

B. $$\frac{{2}}{{5}}$$

C. $$\frac{{8}}{{15}}$$

D. $$\frac{{9}}{{20}}$$

A bag contains 2 red, 3 green and 2 blue balls. Two balls are drawn at random. What is the probability that none of the balls drawn is blue?

A. $$\frac{{10}}{{21}}$$

B. $$\frac{{11}}{{21}}$$

C. $$\frac{{2}}{{7}}$$

D. $$\frac{{5}}{{7}}$$

In a box, there are 8 red, 7 blue and 6 green balls. One ball is picked up randomly. What is the probability that it is neither red nor green?

A. $$\frac{{1}}{{3}}$$

B. $$\frac{{3}}{{4}}$$

C. $$\frac{{7}}{{19}}$$

D. $$\frac{{8}}{{21}}$$

E. $$\frac{{9}}{{21}}$$

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. $$\frac{{1}}{{12}}$$