10th Class Mathematics Probability Question Bank MCQs - Probability

A box contains 100 discs, numbered from 1 to 100. If one disc is drawn at random from the box, then the probability that it bears a prime number less than 30 is

A) \[\frac{7}{100}\]

B) \[\frac{1}{10}\]

C) \[\frac{4}{50}\]

D) \[\frac{9}{50}\]

Correct Answer: B

Solution :

[b] Total number of possible outcomes= 100

Let E be the event 'drawing a prime number less than 30'.

Outcomes favourable to E are

\[\{2,3,5,7,11,13,17,19,23,29\}\]i.e., 10 in number.

\[\therefore \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,P(E)=\frac{10}{100}=\frac{1}{10}\]