10th Class Mathematics Probability Question Bank MCQs - Probability

Someone is asked to take a number from 1 to 100. The probability that it is a prime is: (NCERT EXEMPLAR)

A) \[\frac{1}{5}\]

B) \[\frac{6}{25}\]

C) \[\frac{1}{4}\]

D) \[\frac{13}{50}\]

Correct Answer: C

Solution :

[c] Total number of outcomes = 100

The prime numbers from 1 to 100 are:

\[\{2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,\]\[59,61,67,71,73,79,83,89,97\}.\]

So. favourable number of outcomes = 25

\[\therefore \] Required probability \[=\frac{25}{100}=\frac{1}{4}\]