Question

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. Find the probability that the number on the selected card is not divisible by 3.

Answer 1

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 - \(\frac{1}{3}\) = \(\frac{2}{3}\)