20 cards numbered1,2,3,4,..,19, 20 are put in a box.One boy draws a card from the box.Find the probability that the number on the card is:Prime.

21 cards numbered1,2,3,4,..,19, 20 are put in a box.One boy draws a card from the box.Find the probability that the number on the card is:Divisible by 3

Cards marked with the numbers 2 to101 are placed in a box and mixed thoroughly. One card is drawn from this box. Find the probability that the number of the card is a prime number less than 25.

Cards marked with the numbers 2 to101 are placed in a box and mixed thoroughly. One card is drawn from this box. Find the probability that the number of the card is a number which is a perfect square.

Cards marked with the numbers 2 to101 are placed in a box and mixed thoroughly. One card is drawn from this box. Find the probability that the number of the card is an even number

Cards marked with the numbers 2 to101 are placed in a box and mixed thorougly. One card is drawn from this box. Find the probability that the number of the card is a number less than16

cards marked with numbers 2 to 105 are placed in a box and mixed. one card is chosen at random. The probability that the number on the card is less than 15 is

Suppose 10 cards numbered 1 to 10 are placed in a box and shuffled and one card is drawn at random If A is the event that the number on the card is even, B is the event that the number on the card is more than 3, Find P(A|B)

Suppose 10 cards numbered 1 to 10 are placed in a box and shuffled and one card is drawn at random If A is the event that the number on the card is even, then write A