Total no. of possible outcomes = 30 {1, 2, 3, … 30}
E ⟶ event of getting no. divisible by 3.
No. of favourable outcomes = 10 {3, 6, 9, 12, 15, 18, 21, 24, 27, 30}
Probability, P(E) = (No.of favorable outcomes)/(Total no.of possible outcomes)
P(E) = 10/30 = 1/3
Bar E ⟶ event of getting no. not divisible by 3.
P(Bar E) = 1 – P(E)
= 1 - 1/3 = 2/3