Solution:

The possible outcomes are {1,2,3,….20}

Number of possible outcomes = 20

(i) Let E be the event of getting the number on the card is a prime number.

Outcomes favourable to E are {2,3,5,7,11,13,17,19}

Number of favourable outcomes = 8

P(E) = 8/20 = 2/5

Hence the probability of getting the number on the card is a prime number is 2/5.

(ii) Let E be the event of getting the number on the card is divisible by 3.

Outcomes favourable to E are {3,6,9,12,15,18}

Number of favourable outcomes = 6

P(E) = 6/20 = 3/10

Hence the probability of getting the number on the card is divisible by 3 is 3/10.

(iii) Let E be the event of getting the number on the card is a perfect square.

Outcomes favourable to E are {1,4,9,16}

Number of favourable outcomes = 4

P(E) = 4/20 = 1/5

Hence the probability of getting the number on the card is a perfect square is 1/5.