#### Question

Cards marked with numbers 1, 2, 3, 4… 20 are well shuffled and a card is drawn at random. What is the probability that the number on the card is:

(1) A prime number,

(2) A number divisible by 3,

(3) A perfect square?

#### Solution

Total numbers = 20

1) the prime numbers are 2, 3, 5, 7, 11, 13, 17, 19 respectively

Favourable cases = 8

The probability of getting a prime number = `8/20 = 2/5`

2) the numbers divisible by 3 are 3 ,6 ,9 ,12 ,15 ,18 respectively

Favourable cases =6

Probability of getting a number divisible by 3= `6/20 = 3/10`

3) the perfect squares are 1, 4, 9, 16 respectively

Favourable cases = 4

Probability of getting a perfect square number - `4/20 = 1/5`

Is there an error in this question or solution?

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Cards Marked with Numbers 1, 2, 3, 4… 20 Are Well Shuffled and a Card is Drawn at Random. What is the Probability that the Number on the Card Is: (1) a Prime Number, (2) a Number Divisible by 3, (3) a Perfect Square? Concept: Simple Problems on Single Events.

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