# Probability: Important Questions and Preparation Tips

Get the CBSE Class 10th Mathematics, Probability: Important Questions & Preparation Tips.

Get the CBSE Class 10th Mathematics, Probability: Important Questions & Preparation Tips. This will help with a precise description of the whole chapter along with a gist of each topic covered in the chapter. The Questions mentioned are exclusively topic oriented and are famous for its repetition in many Board papers. Consider the below mentioned points and questions at the time of preparation.

**Important Points:**

In a statement when you find an element of uncertainty, it is measured by the means of **Probability**.

**Experiment:** An activity which ends in a well defined outcome.

**Trial:** An activity performed once, which results in one or several outcomes.

**Random Experiment:** An experiment in which all possible outcomes are known in advance, but the exactness of the result cannot be predicted.

**Event:** An outcome of a random experiment.

**Sample Space:** The set of all possible outcomes in an experiment.

**Equally likely outcomes:** The results of a random experiment are said to be equally likely if the different outcomes have the same chance of occurrence, that is, there is no reason to expect one outcome in preference to another.

**Experimental Probability:** They are based only on estimates which are acquired as a result of actual experiments and adequate recordings of the happening of the event. These estimates might change if the experiment is performed once again.

**Theoretical Probability:** It is what you expect to happen as a result of an experiment, but never actually happens. The theoretical probability of an event E, written as P (E), is defined as

where we assume that the outcomes of the experiment are equally likely.

The probability of a sure event or a certain event is 1 and that the probability of an impossible event is 0.

The probability of an event E is a number P(E) such that

0 ≤ P (E) ≤ 1

**Elementary Event:** An event having only one outcome is called an elementary event. The sum of the probabilities of all the elementary events of an experiment is 1.

**Important Questions:**

- Find the probability of getting a head when a coin is tossed once. Also find the probability of getting a tail.
**(1 mark)** - Two players, Sangeeta and Reshma, play a tennis match. It is known that the probability of Sangeeta winning the match is 0.62. What is the probability of Reshma winning the match?
**(2 mark)** - It is known that a box of 800 electric bulbs contains 16 defective bulbs. One bulb is picked up at random from this box. What is the probability that it is a non-defective bulb.
**(3 mark)** - A bag contains five red balls and some blue balls. If the probability of drawing a blue ball is double that of a red ball, find the number of blue balls in the bag.
**(3 mark)** - Suppose you drop a die at random on the rectangular region as shown in figure. What is the probability that it will land inside a circle of 70 cm diameter.
**(5 mark)**

- Nidhi and nisha are two friends. What is the probability that both will have:
**(5 mark)**- Same birthday
- Different birthday (ignore the leap year)

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