A dice is thrown. What is the probability that the number shown on the dice is not divisible by 3?

Question: A dice is thrown. What is the probability that the number shown on the dice is not divisible by 3?

Solution:
S = {1, 2, 3, 4, 5, 6}
n(S) = 6

Then,
E(not divisible by 3) = {1, 2, 4, 5}
n(E) = 4

∴ P(not divisible by 3) = 4/6
= 2/3