There are 30 cards, of same size, in a bag on which numbers 1 to 30 are written. One card is taken out of the bag at random.

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

Total number of possible outcomes, n(S) = 30 

Number of favorable outcomes of selecting a card divisible by 3, 

n(E) = 10

∴ P(E) = \(\frac{n(E)}{n(S)}\) = \(\frac{10}{30}\) = \(\frac{1}{3}\)

Number of favorable outcomes of not selecting a card divisible by 3 = 1 – P(E)

= 1 - \(\frac{1}{3}\) = \(\frac{2}{3}\)