Class 7: Maths Chapter 25 solutions. Complete Class 7 Maths Chapter 25 Notes.
Contents
RD Sharma Solutions for Class 7 Maths Chapter 25–Data Handling – IV (Probability)
RD Sharma 7th Maths Chapter 25, Class 7 Maths Chapter 25 solutions
1. A coin is tossed 1000 times with the following frequencies:
Head: 445, Tail: 555
When a coin is tossed at random, what is the probability of getting?
(i) A head?
(ii) A tail?
Solution:
Given total number of times a coin is tossed = 1000
Number of times a head comes up = 445
Number of times a tail comes up = 555
(i) Probability of getting head = number of heads/total number of trails
= (445/1000)
= 0.445
(ii) Probability of getting tail = number of tail/total number of trails
= (555/1000)
= 0.555
2. A die is thrown 100 times and outcomes are noted as given below:
| Outcome | 1 | 2 | 3 | 4 | 5 | 6 |
| Frequency | 21 | 9 | 14 | 23 | 18 | 15 |
If a die is thrown at random, find the probability of getting a/an:
(i) 3
(ii) 5
(iii) 4
(iv) Even number
(v) Odd number
(vi) Number less than 3.
Solution:
Given total number of trials = 100
(i) From the table, number of times 3 comes up = 14
Probability of getting 3 = frequency of 3/ total number of trails
= 14/100
= 7/50
(ii) From the table, number of times 5 comes up = 18
Probability of getting 5 = frequency of 5/ total number of trails
= 18/100
= 9/50
(iii) From the table, number of times 4 comes up = 23
Probability of getting 4 = frequency of 4/ total number of trails
= 23/100
(iv) Frequency of getting an even number = Frequency of 2 + Frequency of 4 + Frequency of 6
= 9 + 23 + 15
= 47
Probability of getting an even number = frequency of an even number/ total number of trails
= 47/100
(v) Frequency of getting an even number = Frequency of 1 + Frequency of 3 + Frequency of 5
= 21 + 14 + 18
= 53
Probability of getting odd number = frequency of odd number/ total number of trails
= 53/100
(vi) Frequency of getting number less than 3 = Frequency of 1 + Frequency of 2
= 21 + 9
= 30
Probability of getting number less than 3 = frequency of number less than 3/ total number of trails
= 30/100
= 3/10
3. A box contains two pair of socks of two colours (black and white). I have picked out a white sock. I pick out one more with my eyes closed. What is the probability that I will make a pair?
Solution:
Given number of socks in the box = 4
Let B and W denote black and white socks respectively. Then we have
S = {B, B, W, W}
If a white sock is picked out, then the total no. of socks left in the box = 3
Number of white socks left = 2 – 1 = 1
Probability of getting white socks = number of white socks left in the box/ total number of socks left in the box
= 1/3
4. Two coins are tossed simultaneously 500 times and the outcomes are noted as given below:
| Outcome: | Two heads (HH) | One head (HT or TH) | No head (TT) |
| Frequency: | 105 | 275 | 120 |
If same pair of coins is tossed at random, find the probability of getting:
(i) Two heads
(ii) One head
(iii) No head.
Solution:
Given number of trials = 500
From the given table it is clear that,
Number of outcomes of two heads (HH) = 105
Number of outcomes of one head (HT or TH) = 275
Number of outcomes of no head (TT) = 120
(i) Probability of getting two heads = frequency of getting 2 heads/ total number of trials
= 105/500
= 21/100
(ii) Probability of getting one head = frequency of getting 1 heads/ total number of trials
= 275/500
= 11/20
(iii) Probability of getting no head = frequency of getting no heads/ total number of trials
= 120/500
= 6/25
RD Sharma Solutions for Class 7 Maths Chapter 25: Download PDF
RD Sharma Solutions for Class 7 Maths Chapter 25–Data Handling – IV (Probability)
Download PDF: RD Sharma Solutions for Class 7 Maths Chapter 25–Data Handling – IV (Probability) PDF
Chapterwise RD Sharma Solutions for Class 7 Maths :
- Chapter 1–Integers
- Chapter 2–Fractions
- Chapter 3–Decimals
- Chapter 4–Rational Numbers
- Chapter 5–Operations On Rational Numbers
- Chapter 6–Exponents
- Chapter 7–Algebraic Expressions
- Chapter 8–Linear Equations in One Variable
- Chapter 9–Ratio And Proportion
- Chapter 10–Unitary Method
- Chapter 11–Percentage
- Chapter 12–Profit And Loss
- Chapter 13–Simple Interest
- Chapter 14–Lines And Angles
- Chapter 15–Properties of Triangles
- Chapter 16–Congruence
- Chapter 17–Constructions
- Chapter 18–Symmetry
- Chapter 19–Visualising Solid Shapes
- Chapter 20–Mensuration – I (Perimeter and area of rectilinear figures)
- Chapter 21–Mensuration – II (Area of Circle)
- Chapter 22–Data Handling – I (Collection and Organisation of Data)
- Chapter 23–Data Handling – II Central Values
- Chapter 24–Data Handling – III (Constructions of Bar Graphs)
- Chapter 25–Data Handling – IV (Probability)
About RD Sharma
RD Sharma isn’t the kind of author you’d bump into at lit fests. But his bestselling books have helped many CBSE students lose their dread of maths. Sunday Times profiles the tutor turned internet star
He dreams of algorithms that would give most people nightmares. And, spends every waking hour thinking of ways to explain concepts like ‘series solution of linear differential equations’. Meet Dr Ravi Dutt Sharma — mathematics teacher and author of 25 reference books — whose name evokes as much awe as the subject he teaches. And though students have used his thick tomes for the last 31 years to ace the dreaded maths exam, it’s only recently that a spoof video turned the tutor into a YouTube star.
R D Sharma had a good laugh but said he shared little with his on-screen persona except for the love for maths. “I like to spend all my time thinking and writing about maths problems. I find it relaxing,” he says. When he is not writing books explaining mathematical concepts for classes 6 to 12 and engineering students, Sharma is busy dispensing his duty as vice-principal and head of department of science and humanities at Delhi government’s Guru Nanak Dev Institute of Technology.