Question

# A page is opened at random from a book containing 90 pages. Then the probability of a page number is a perfect square, is ___.

Hint:In the above question, number of pages in the book is 90 pages which would be taken as Total cases. Number of perfect squares between 1 to 90 is the favorable case. So, the probability of a page number is equal to the number of perfect squares (favorable cases) divided by total cases.

Probability of a page number is a perfect square $= \dfrac{9}{{90}} = \dfrac{1}{{10}}$
Therefore, probability is $\dfrac{1}{{10}}$.
Note:Probability can also be called as possibility.It is expressed between 0 to 1, where 0 means the event is impossible and 1 means an event is certain. Probability is the measure of an event to occur. The probability of all the events in a sample space is equal to 1. For example – When a die is thrown, there are six possible outcomes – 1, 2, 3, 4, 5, 6. Then the probability of any one of them is $\dfrac{1}{6}$. In general, the probability of an event happening is the number of ways it can happen divided by the total number of outcomes.