Blood Group | Number of students |

O | 12 |

A | 9 |

B | 6 |

AB | 3 |

Answer :

Number of students having blood group AB = 3

Total number of students = 30

Hence, required probability is \(P = \frac{3}{30} = \frac{1}{10}\).

Therefore, the probability that a student of this class, selected at random, has blood group AB is \(\frac{1}{10}\).

- In a cricket match, a batswoman hits a boundary 6 times out of 30 balls she plays. Find the probability that she did not hit a boundary.
- 1500 families with 2 children were selected randomly, and the following data were recorded:No. of girls in a family210No. of families475814211Compute the probability of a family,chosen at random, havingi) 2 girlsii) 1 girliii) no girlAlso check weather the sum of these probabilities is 1.
- Refer to Example 5, Section 14.4, Chapter 14. Find the probability that a student of the class was born in August.
- Three coins are tossed simultaneously 200 times with the following frequencies of different outcomes:Outcome3 heads2 heads1 heads0 headFrequency23727728If the three coins are simultaneously tossed again, compute the probability of 2 heads coming up.
- An organisation selected 2400 families at random and surveyed them to determine a relationship between income level and the number of vehicles in a family. The information gathered is listed in the table below: Monthly Income (in Rs.)Vehicles per family 012Above 2 Less than 700010160250 7000 - 100000305272 10000 - 130001535291 1300 - 1600024695925 1600 or more15798288 Suppose a family is chosen, find the probability that the family chosen isi) earning Rs 10000 — 13000 per month and owning exactly 2 vehicles.ii) earning Rs 16000 or more per month and owning exactly I vehicle.iii) earning less than Rs 7000 per month and does not own any vehicle.iv) earning Rs 13000 — 16000 per month and owning more than 2 vehicles.v) owning not more than 1 vehicle.
- Refer to Table 14.7, Chapter 14.i) Find the probability that a student obtained less than 20% in the mathematics test.ii) Find the probability that a student obtained marks 60 or above.
- To know the opinion of the students about the subject statistics, a survey of 200 students was conducted. The data is recorded in the following table.OpinionNumber of studentslike135Dislike65Find the probability that a student chosen at randomi) likes statisticsii) does not like it.
- Refer to Q.2, Exercise 14.2. What is the empirical probability that an engineer lives: i) less than 7 km from her place of work?ii) more than or equal to 7 km from her place of work?iii) within \(\frac{1}{2}\) km from her place of work?
- Activity : Note the frequency of two-wheelers, three-wheelers and four-wheelers going past during a time interval, in front of your school gate. Find the probability that any one vehicle out of the total vehicles you have observed is a two-wheeler.
- Activity : Ask all the students in your class to write a 3-digit number. Choose any student from the room at random. What is the probability that the number written by her/him is divisible by 3? Remember that a number is divisible by 3, if the sum of its digits is divisible by 3.
- Eleven bags of wheat flour, each marked 5 kg, actually contained the following weights of flour (in kg): 4.97 5.05 5.08 5.03 5.00 5.06 5.08 4.98 5.04 5.07 5.00Find the probability that any of these bags chosen at random contains more than 5 kg of flour.
- In Q.5, Exercise 14.2, you were asked to prepare a frequency distribution table, regarding the concentration of sulphur dioxide in the air in parts per million of a certain city for 30 days.Using this table, find the probability of the concentration of sulphur dioxide in the interval 0.12 - 0.16 on any of these days. Concentration of \(S\left(O_{2}\right) \) (in ppm)Number of days (frequency) 0.00 - 0.044 0.04 - 0.089 0.08 - 0.129 0.12 - 0.162 0.16 - 0.204 0.20 - 0.242 Total30

- NCERT solutions for class 9 maths chapter 1 Number Systems
- NCERT solutions for class 9 maths chapter 2 Polynomials
- NCERT solutions for class 9 maths chapter 3 Coordinate geometry
- NCERT solutions for class 9 maths chapter 4 Linear equations in two variables
- NCERT solutions for class 9 maths chapter 5 Introduction to Euclidean Geometry
- NCERT solutions for class 9 maths chapter 6 Lines and Angles
- NCERT solutions for class 9 maths chapter 7 Triangles
- NCERT solutions for class 9 maths chapter 8 Quadrilaterals
- NCERT solutions for class 9 maths chapter 9 Areas of parallelograms and triangles
- NCERT solutions for class 9 maths chapter 10 Circles
- NCERT solutions for class 9 maths chapter 11 Constructions
- NCERT solutions for class 9 maths chapter 12 Heron's Formula
- NCERT solutions for class 9 maths chapter 13 Surface areas and volumes
- NCERT solutions for class 9 maths chapter 14 Statistics
- NCERT solutions for class 9 maths chapter 15 Probability

- NCERT solutions for class 9 science chapter 1 Matter in our Surroundings
- NCERT solutions for class 9 science chapter 2 Is Matter Around Us Pure
- NCERT solutions for class 9 science chapter 3 Atoms and Molecules
- NCERT solutions for class 9 science chapter 4 Structure of the Atom
- NCERT solutions for class 9 science chapter 5 The Fundamental Unit of Life
- NCERT solutions for class 9 science chapter 6 Tissues
- NCERT solutions for class 9 science chapter 7 Diversity in Living Organisms
- NCERT solutions for class 9 science chapter 8 Motion
- NCERT solutions for class 9 science chapter 9 Force and Laws of Motion
- NCERT solutions for class 9 science chapter 10 Gravitation
- NCERT solutions for class 9 science chapter 11 Work and Energy
- NCERT solutions for class 9 science chapter 12 sound
- NCERT solutions for class 9 science chapter 13 Why do We Fall Ill
- NCERT solutions for class 9 science chapter 14 Natural Resources
- NCERT solutions for class 9 science chapter 15 Improvement in Food Resources