Answer:
a) The number of possible codes is 16384
b) The probability of entering the code on the firs ttry is 1/16384
Step-by-step explanation:
a) For each of the four digits we have 7 possibilities and the number of one digit doesnt make restrictions on the others, thus, we have to power 4 a total of 7 times. The number of codes available is 4⁷ = 16384
b) There is only 1 code favourable over a total of 16384, as a consequence, the probability of enter the code correctly is 1/16384