# RD SHARMA Solutions for Class 9 Maths Chapter 25 - Probability

## Chapter 25 - Probability Exercise Ex. 25.1

Head : 455, Tail : 545

Compute the probability for each event.

Two coins are tossed simultaneously 500 times with the following frequencies of different outcomes:

Two heads : 95 times

One tail : 290 times

No head : 115 times

Find the probability of occurrence of each of these events.

Number of girls in a family: | 0 | 1 | 2 |

Number of families: | 211 | 814 | 475 |

If a family is chosen at random, compute the probability that it has:

(i) No girl

(ii) 1 girl

(iii) 2 girls

(iv) at most one girl

(v) more girls than boys

Find the probability that on a ball played:

(i) he hits boundary

(ii) he does not hit a boundary.

Units Test: | I | II | III | IV | V |

Percentage of marks obtained: | 69 | 71 | 73 | 68 | 76 |

Find the probability that the student gets:

(i) More than 70% marks

(ii) less than 70% marks

(iii) a distinction.

Following table shows the birth month of 40 students of class IX. |
|||||||||||

Jan |
Feb |
March |
April |
May |
June |
July |
Aug. |
Sept. |
Oct. |
Nov. |
Dec. |

3 |
4 |
2 |
2 |
5 |
1 |
2 |
5 |
3 |
4 |
4 |
4 |

Find the probability that a student was born in August. |

## Chapter 25 - Probability Exercise 25.16

The probability of an impossible event is

(a) 1

(b) 0

(c) less than 0

(d) greater than 1

The probability of an impossible event is always zero since the chances of occurring of that event is zero.

Hence, correct option is (b).

The probability of a certain event is

(a) 0

(b) 1

(c) greater than 1

(d) less than 0

The probability an event of a trial is

(a) 1

(b) 0

(c) less than 1

(d) more than 1

## Chapter 25 - Probability Exercise 25.17

A coin is tossed 1000 times, if the probability of getting a tail is 3/8, how many times head is obtained?

(a) 525

(b) 375

(c) 625

(d) 725

A dice is rolled 600 times and the occurrence of the outcomes 1, 2, 3, 4, 5 and 6 are given below:

Outcome | 1 | 2 | 3 | 4 | 5 | 6 |

frequency | 200 | 30 | 120 | 100 | 50 | 100 |

The probability of getting a prime number is

The percentage of attendance of different classes in a year in a school is given below:

Class: | X | IX | VIII | VII | VI | V |

Attendance: | 30 | 62 | 85 | 92 | 76 | 55 |

What is the probability that the class attendance is more than 75%?

A bag contains 50 coins and each coin is marked from 51 to 100. One coin is picked at random. The probability that the number on the coin is not a prime number, is

In a football match, Ronaldo makes 4 goals from 10 penalty kicks. The probability of converting a penalty kick into a goal by Ronaldo, is

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