Persons are sitting in a row. Two of them are selected. Write the probability that they are together.

Suppose n ( >=3) persons are sitting in a row. Two of them are selected at random. The probability that they are not together is (A) 1- 2/n (B) 2/(n-1) (C) 1- 1/n (D) nonoe of these

Statement-1: 20 persons are sitting in a row. Two of these persons are selected at random. The probability that the two selected persons are not together is 0.9. Statement-2 :If overline(A) denotes the negation of an event A, then P(overline(A))=1-P(A) .

There are m persons sitting in a row. Two of the mare selected at random. The probability that the two selected persons are together

(n>=5) persons are sitting in a row. Three of these are selected at random. The probability that no two of the selected persons sit together is

6 boys and 6 girls sit in a row at random. Find the probability that all the girls sit together.

6 boys and 6 girls sit in a row at random. Find the probability that all the girls sit together.

Six '+' signs and five '-' signs are to be arranged in a row. If the arrangement is at random, then the probability that no 2 '-' sings are together, is

15 persons are sitting in a row. In how many ways we can select three of them if adjacent persons are not selected?

5 boys and 5 girls sit in a row randomly. Find the probability that all the boys sit together.

There are 7 seats in a row. Three persons take seats at random the probability that the middle seat is always occupied and no two persons are consecutive is