Question

Cards marked with the numbers 2 to 101 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. an even number 

b. a number less than 16 

c. a number which is a perfect square 

d. a prime number less than 25

Answer 1

a. \(\frac{1}{2}\)

b. \(\frac{14}{100}=\frac{7}{50}\)

c. The perfect squares are 4, 9, 16, ..... 100 probability = \(\frac{9}{100}\)

d. The prime numbers less than 25 are 2, 3, 5, 7, 11, 13, 17, 19, 23.

probability = \(\frac{9}{100}\)

When probabilities are explained in terms of numbers it is the ratio of number of favorable outcomes to the total number of outcomes.

The least probability will be 0 and the highest will be 1. The probability will be a number between 0 and 1.

If an event can be completed in ‘m’ ways and another event can be completed in ‘n’ ways then both the events can be completed one after the other in m x n ways.