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 when AAAA is transmitted, ABCA

is received on the receiver.