Assume that the probability of error-free transmission of a message over a communication channel is p. If a message is not transmitted correctly, a retransmission is initiated. This procedure is repeated until a correct transmission occurs. Such a channel is often called a feedback channel. Assuming that successive transmissions are independent, what is the probability that: a) No retransmission is required. b) Exactly two retransmissions are required

This question is incomplete, the complete question is;

Assume that the probability of error-free transmission of a message over a communication channel is p=0.9. If a message is not transmitted correctly, a retransmission is initiated. This procedure is repeated until a correct transmission occurs. Such a channel is often called a feedback channel. Assuming that successive transmissions are independent, what is the probability that:

a) No retransmission is required.

b) Exactly two retransmissions are required

a) probability that No retransmission is required is  0.90

b) the probability that exactly two retransmissions are required is 0.009

Step-by-step explanation:

Given the data in the question;

the probability of error-free transmission of a message over a communication channel is p = 0.9

a) probability that No retransmission is required will be;

Let x represent the error-free transmission of a message

Now, the P( error-free_transmission_of_a_message) = 0.90

so;

P( X=0 ) = 0.90( 1 - 0.90 )⁰

P( X=0 ) = 0.90( 0.1 )⁰

P( X=0 ) = 0.90( 1 )

P( X=0 ) = 0.90

Therefore, probability that No retransmission is required is  0.90

b) Probability that exactly two retransmissions are required will be;

P( X=2 ) = 0.90( 1 - 0.90 )²

P( X=2 ) = 0.90( 0.1 )²

P( X=2 ) = 0.90( 0.01)

P( X=2 ) = 0.009

Therefore, the probability that exactly two retransmissions are required is 0.009

he spend 5.1 minutes chatting with his friends.

step-by-step explanation:

2/5+1/2=9/10

6/1-9/10=5.1