- Trending Categories
- Data Structure
- Networking
- RDBMS
- Operating System
- Java
- iOS
- HTML
- CSS
- Android
- Python
- C Programming
- C++
- C#
- MongoDB
- MySQL
- Javascript
- PHP

- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who

# A box contains 90 discs which are numbered from 1 to 90. If one disc is drawn at random from the box, find the probability that it bears

**(i)** a two digit number.

**(ii)** a perfect square number.

**(iii)** a number divisible by 5.

Given:

A box contains 90 discs which are numbered from 1 to 90.

One disc is drawn at random from the box.

To do:

We have to find the probability that it bears

(i) a two digit number.

(ii) a perfect square number.

(iii) a number divisible by 5.

Solution:

A box contains discs numbered \( 1,2,3,4, .., 89,90 \).

This implies,

The total number of possible outcomes $n=90$.

(i) Two digit numbers from 1 to 90 are $10, 11, .........., 89, 90$.

Total number of favourable outcomes $=81$.

We know that,

Probability of an event $=\frac{Number\ of\ favourable\ outcomes}{Total\ number\ of\ possible\ outcomes}$

Therefore,

Probability that the disc bears a two digit number $=\frac{81}{90}$

$=\frac{9}{10}$

The probability that it bears a two digit number is $\frac{9}{10}$.

(ii) Perfect square numbers from 1 to 90 are $1, 4, 9, 16, 25, 36, 49, 64, 81$.

Total number of favourable outcomes $=9$.

We know that,

Probability of an event $=\frac{Number\ of\ favourable\ outcomes}{Total\ number\ of\ possible\ outcomes}$

Therefore,

Probability that the disc bears a perfect square number $=\frac{9}{90}$

$=\frac{1}{10}$

The probability that it bears a perfect square number is $\frac{1}{10}$.

(iii) Numbers divisible by 5 from 1 to 90 are $5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90$.

Total number of favourable outcomes $=18$.

We know that,

Probability of an event $=\frac{Number\ of\ favourable\ outcomes}{Total\ number\ of\ possible\ outcomes}$

Therefore,

Probability that the disc bears a number divisible by 5 $=\frac{18}{90}$

$=\frac{1}{5}$

The probability that it bears a number divisible by 5 is $\frac{1}{5}$.

- Related Questions & Answers
- Which property is used to tell the browser what to do if the box's content is larger than the box itself?
- What is the difference between a white box, black box, and gray box testing?
- Retrieve from MySQL only if it contains two hyphen symbols?
- What are the differences between Box and Ubuntu One?
- How to create a 90-degree arc in R?
- Select rows from a table with date between 90 days ago and now in MySQL
- Find the position of box which occupies the given ball in Python
- How can I rotate xtick labels through 90 degrees in Matplotlib?
- How to remove rows from an R data frame that contains at least one NaN?
- Find the probability of a state at a given time in a Markov chain - Set 1 in Python
- Set the maximum height that a box can be with CSS
- Set the minimum height that a box can be with CSS
- Set the maximum width that a box can be with CSS
- Set the minimum width that a box can be with CSS
- What is a Grey Box Testing?
- Find the number of integers from 1 to n which contains digits 0’s and 1’s only in C++