RD Sharma Solutions Class 9 Maths Chapter 25: RD Sharma Solutions for Class 9 Maths Chapter 25 - Probability provide students with a comprehensive understanding of the fundamental concepts of probability. This chapter covers topics such as theoretical probability, experimental probability, and various rules and formulas related to probability calculations.
With step-by-step explanations and solved examples, these solutions help students grasp the concepts effectively. Practicing with RD Sharma Solutions for Class 9 Maths Chapter 25 enhances problem-solving skills and prepares students for exams. Whether you're learning about probability for the first time or revising the concepts, these solutions are a valuable resource to strengthen your mathematical knowledge.CBSE Class 9 Science Syllabus 2024-25
RD Sharma Solutions Class 9 Maths Chapter 25 PDF
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Question 1: A coin is tossed 1000 times in the following sequence:
Head: 455, Tail: 545
Compute the probability of each event.
Solution:
The coin is tossed 1000 times, which means the number of trials is 1000. Let us consider the event of getting head and the event of getting tail be E and F, respectively. Number of favourable outcomes = Number of trials in which the E happens = 455 So, probability of E = (Number of favourable outcomes) / (Total number of trials) P(E) = 455/1000 = 0.455 Similarly, Number of favourable outcomes = Number of trials in which the F happens = 545 Probability of the event getting a tail, P(F) = 545/1000 = 0.545Question 2: 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.
Solution:
We know that, Probability of any event = (Number of favourable outcomes) / (Total number of trials) Total number of trials = 95 + 290 + 115 = 500 Now, P(Getting two heads) = 95/500 = 0.19 P(Getting one tail) = 290/500 = 0.58 P(Getting no head) = 115/500 = 0.23Question 3: Three coins are tossed simultaneously 100 times with the following frequencies of different outcomes:
Outcome | No head | One head | Two heads | Three heads |
Frequency | 14 | 38 | 36 | 12 |
If the three coins are simultaneously tossed again, compute the probability of:
(i) 2 heads coming up
(ii) 3 heads coming up
(iii) At least one head coming up
(iv) Getting more heads than tails
(v) Getting more tails than heads
Solution:
We know, Probability of an event = (Number of Favorable outcomes) / (Total Number of outcomes) In this case, the total number of outcomes = 100.(i) Probability of 2 Heads coming up = 36/100 = 0.36
(ii) Probability of 3 Heads coming up = 12/100 = 0.12
(iii) Probability of at least one head coming up = (38+36+12) / 100 = 86/100 = 0.86
(iv) Probability of getting more Heads than Tails = (36+12)/100 = 48/100 = 0.48
(v) Probability of getting more tails than heads = (14+38) / 100 = 52/100 = 0.52
Question 4: 1500 families with 2 children were selected randomly, and the following data were recorded:
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
Solution:
We know, Probability of an event = (Number of Favorable outcomes) / (Total number of outcomes) In this case, the total number of outcomes = 211 + 814 + 475 = 1500. (Here, total numbers of outcomes = total number of families)(i) Probability of having no girl = 211/1500 = 0.1406
(ii) Probability of having 1 girl = 814/1500 = 0.5426
(iii) Probability of having 2 girls = 475/1500 = 0.3166
(iv) Probability of having at the most one girl = (211+814) /1500 = 1025/1500 = 0.6833
(v) Probability of having more girls than boys = 475/1500 = 0.31
Question 5: In a cricket match, a batsman hits a boundary 6 times out of 30 balls he plays. Find the probability that on a ball played:
(i) He hits a boundary (ii) He does not hit a boundary.
Solution:
Total number of balls played by a player = 30 Number of times he hits a boundary = 6 Number of times he does not hit a boundary = 30 – 6 = 24 We know, Probability of an event = (Number of Favorable outcomes) / (Total number of outcomes) Now,(i) Probability (he hits boundary) = (Number of times he hit a boundary) / (Total number of balls he played)
= 6/30 = 1/5(ii) Probability that the batsman does not hit a boundary = 24/30 = 4/5
Question 6: The percentage of marks obtained by a student in monthly unit tests is given below:
Find the probability that the student gets
(i) More than 70% marks
(ii) Less than 70% marks
(iii) A distinction
Solution:
Total number of unit tests taken = 5 We know, Probability of an event = (Number of Favorable outcomes) / (Total number of outcomes)(i) Number of times student got more than 70% = 3
Probability (Getting more than 70%) = 3/5 = 0.6(ii) Number of times student got less than 70% = 2
Probability (Getting less than 70%) = 2/5 = 0.4(iii) Number of times student got a distinction = 1
[Marks more than 75%] Probability (Getting a distinction) = 1/5 = 0.2Question 7: To know the opinion of the students about Mathematics, a survey of 200 students was conducted. The data was recorded in the following table:
Find the probability that students chosen at random:
(i) Likes Mathematics (ii) Does not like it.
Solution:
Total number of students = 200 Students like mathematics = 135 Students dislike Mathematics = 65 We know, Probability of an event = (Number of Favorable outcomes) / (Total number of outcomes) (i) Probability (Student likes mathematics) = 135/200 = 0.675 (ii) Probability (Student does not like mathematics) = 65/200 = 0.325CBSE Class 9 Maths Syllabus | CBSE Class 9 Science Syllabus |
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