On a communication channel one of three sequences of letters can be transmitted: AAAA, BBBB, CCCC. It is known that the action of noise on the receiver decreases the probability of correct reception of a transmitted letter to 0.6. The probability of the incorrect reception of a transmitted letter as either of the two other letters increases to 0.2. It is assumed that the letters are distorted independently of one another. Find the probability that

1) When AA is transmitted, AB is received on the receiver

2) When AAAA is transmitted, ABCA is received on the receiver

Please give me the explanation and ipynb file also