Some question: A password of a computer consists of five digits 1 through 6. What is the probability that all digits are divisible by 3 ?
Options:
(A) 1/3
(B) 1/6
(C) 1/27
(D) 1/243
(E) 1/486
Some stream of consciousness:
For each digit there are six possibilities. Two of them (3 and 6) are divisible by three, so there is a one in three chance for each digit, and since the digits are independent of each other, overall probability is 1 / 3^5 or The answer: (D).