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  • Seven persons are to be seated in a row. The probability that two particular persons sit next to each other is A. 1 /3 B. 1/ 6 C. 2 / 7 D. 1 / 2

Seven persons are to be seated in a row. The probability that two particular persons sit next to each other is
A. 1/3

B. 1/6

C. 2/7

D. 1/2
 

Answers (1)

7 persons are to be seated in a row   ….. (given)

Let us consider 2 persons as 1 group since 2 persons sit next to each other.

Thus, we have to arrange 6 persons.

Thus, the number . of arrangement = 2! X 6!

Thus, total number . of arrangement of 7 persons = 7!

Now,

Probability = number of favourable outcomes/total numbers of outcomes

                        = 2! X 6! / 7!

                        = 2 x 1 x 6! / 7 x 6!

                        = 2/ 7

Thus, option C is the correct answer.

Posted by

infoexpert22

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