Adormitory has n students, all of whom like to gossip. one of the students hears a rumor, and tells it to one of the other n − 1 students picked at random. subsequently, each student who hears the rumor tells it to a student picked at random from the dormitory (excluding, of course, himself/herself and the person from whom he/she heard the rumor). let pr be the probability that the rumor is told r times without coming back to a student who has already

Step-by-step explanation:

From the question, we have the following condition:

We know that each student who hears the rumor tells it to a student picked at random from the dormitory (excluding, of course, himself/herself and the person from whom he/she heard the rumor)

The 3rd student can therefore tell the rumour to n-2 students but only n-3 will accept it.

Consequently, the 4th student must not tell the 1st and second students.

We can rewrite this to observe a pattern:

Hence, the probability that the rumor is told r times without coming back to a student who has already is:

See attachment for complete question

it should be a and d. lmk if i'm wrong xd

it is a. 4.2 because 7.6-3.4 gets the remaining length of 4.2. i might be wrong but i am pretty sure this is the answer.