Edudel, Directorate of Education Govt. of NCT of Delhi Class 8 Mental Maths Chapter 5 Data Handling Questions Solution. In this chapter, there is total 50 math problems. We have given each questions solution step by step.
1.) Data available in an unorganized form is called ____ data.
Answer:
Data available in an unorganized form is called Raw data.
2.) Data represented using circle is known as _______.
Answer:
Data represented using circle is known as Pie Chart.
3.) In the class interval 26-33, 33 is known as ______.
Answer:
In the class interval 26-33, 33 is known as Upper Class Limit.
4.) The number of times a particular observation occurs in a given data is called its _______.
Answer:
The number of times a particular observation occurs in a given data is called its Frequency.
5.) Numbers 1 to 15 are written on separate slips i.e. one number on one slip and they are put in a box. Radha pick a slip from the box without looking at it. What is the probability that slip bears an odd number?
Answer:
Given that,
Numbers 1 to 15 are written on separate slips. One number on one slip
Radha pick a slip from the box without looking at it
We have to find, probability that slip bears an odd number.
We know,
= /
To find Total Odd number or .
15 + 1 / 2 = 8
There are total 8 Odd number.
Total number is 15.
= total Odd number / Total number
= 8 / 15
6.) A dice is thrown once. Find the probability of getting a multiple of 2 or 3.
Answer:
When we throw a dice, number of sample space is n= 6
{1, 2, 3, 4, 5, 6}
Now, we have to find probability of getting a multiple of 2 or 3.
Multiple of 2 or 3 are 2,3,4,6. N= 4
We know,
= /
Probability of getting a multiple of 2 or 3 = multiple of 2 or 3 / Total Number
Probability of getting a multiple of 2 or 3 = 4 / 6
Probability of getting a multiple of 2 or 3 = 2 / 3
7.) A family plays a game with a dice. In a single thrown of dice, getting a prime number means father wins and getting an even number means son wins. Find the probability that both will win simultaneously.
Answer:
Given that,
A family plays a game with a dice. In a single thrown of dice.
When we throw a dice, number of sample space is n= 6
{1, 2, 3, 4, 5, 6}
Getting a prime number means father wins and getting an even number means son wins.
We have to find probability that both will win simultaneously.
We know,
2 is the only number which is prime number and also even Number.
Probability that both will win simultaneously = 2 / 6
Probability that both will win simultaneously = 1 / 3
8.) Find the range of the data 8, 15, 51, 62, 8, 72, 0 and 35.
Answer:
Given data 8, 15, 51, 62, 8, 72, 0 and 35.
We have to find range of the data.
We know,
The difference of highest value and the lowest value of observation is known as range.
Highest Value = 72
Lowest Value = 0
Range = 72 – 0 = 72
9.) A bag contains 80 red balls, 30 white balls and few blue balls. Find the number of blue balls in the bag if the probability of a getting a red ball is /.
Answer:
Given that,
A bag contains 80 red balls, 30 white balls and few blue balls.
We have to find number of blue balls in the bag if the probability of a getting a red ball is /.
Given that, Total red ball = 80
We know,
= /
of red balls = Number of red balls / Total number of balls in bag
of red balls = 80 / Total number of balls in bag
2 / 3 = 80 / Total number of balls in bag
By cross multiplication,
Total number of balls in bag = 120
Total number of balls in bag = Number of red balls + Number of white balls + Number of blue balls
120 = 80 + 30 + Number of blue balls
Number of blue balls = 10
10.) The given pie chart shows the percentage breakdown of 800 votes in student’s elections. How many votes did Reena receive?
Answer:
Given, percentage breakdown of 800 votes in student’s elections.
We have to find votes did Reena receive.
Reena receive 25 % vote.
100 % = 800 votes
25 % = ?
By cross Multiplication,
25 % = 200 votes.
Reena receive 200 votes.
11.) A card is drawn from a well shuffled pack of 52 cards. Find the probability of getting neither a red card nor a queen.
Answer:
A card is drawn from a well shuffled pack of 52 cards.
We have to find probability of getting neither a red card nor a queen.
We know,
= /
Now, in 52 cards there are 24 cards which are neither a red card nor a queen.
= Number of cars which are neither a red card nor a queen./ Total number
= 24 / 52
= 6 / 13
12.) Cards are marked from 10 to 100. A card is chosen at random. What is the probability of getting a perfect number?
Answer:
Cards are marked from 10 to 100. A card is chosen at random.
From 10 to 100 there are 91 cards.
We have to find probability of getting a perfect number.
There is only 1 card getting a perfect number.
= /
Probability of getting a perfect number = 1 / 91
13.) Two coins are thrown simultaneously. Find the probability of getting atmost one head.
Answer:
Two coins are thrown simultaneously.
Sample space are (HH, HT, TH, TT) = n = 4
We have to find probability of getting atmost one head.
Numbers of getting atmost one head = (HH, HT, TH) = 3
= /
of getting atmost one head = 3 / 4
14.) Two dice are thrown simultaneously. Find the probability of getting the same number on both the dice.
Answer:
Two dice are thrown simultaneously.
Number of sample space is n = 36.
We have to find probability of getting the same number on both the dice.
Sample space getting the same number on both the dice = {(1,1), (2,2), (3,3), (4,4), (5,5), (6,6)} = n = 6
= /
getting the same number on both the dice = 6 / 36 = 1/ 6
15.) Ravi scored 12, 92, 0 and 16 runs in the 4 innings. Find the average runs scored by him.
Answer:
Ravi scored 12, 92, 0 and 16 runs in the 4 innings.
We have to find average runs scored by him
Average = Sum of Runs / Number of innings
Average = 12 + 92 + 0 + 16 / 4
Average = 120 / 4
Average = 30
16.) Find the class mark of class Interval 1000-1100.
Wages | Number of workers |
800 – 900 | 7 |
900 – 1000 | 13 |
1000 – 1100 | 2 |
1100 – 1200 | 8 |
1200-1300 | 10 |
Answer:
In class 1000-1100 there are 2 workers.
The class mark of class Interval 1000-1100 = 1000 + 1100 / 2
The class mark of class Interval 1000-1100 = Rs. 1050
17.) In a multiple choice question with 5 options, Ranjeet randomly answered one question. Find the probability that he answered it correctly.
Answer:
In a multiple choice question with 5 options, Ranjeet randomly answered one question
We have to find probability that he answered it correctly.
We know,
= /
Probability that he answered it correctly = 1 / 5
18.) In a hostel the following students speak different languages. If a pie chart is formed, find the central angle made by Bengali speaking students.
Language spoken | English | Hindi | Marathi | Bengali |
Number of students | 34 | 12 | 16 | 10 |
Answer:
We have to find central angle made by Bengali speaking students.
Number of students Bengali speaking = 10
Total number of students = 72
= / × °
Central angle made by Bengali speaking students = Number of students Bengali speaking / Total number of students × °
Central angle made by Bengali speaking students = (10 / 72) × °
Central angle made by Bengali speaking students = 5°
19.) Find the probability that a leap year selected at random will have 53 Tuesdays.
Answer:
We know, Leap year has 366 days.
We have to find probability that a leap year selected at random will have 53 Tuesdays.
Probability that a leap year selected at random will have 53 Tuesdays = / 7
20.) Find the probability that a number selected from the numbers 1,2,3,4…..30, is a perfect square number.
Answer:
The numbers 1,2,3,4…..30
n = 30
We have to find probability that a number selected a perfect square number.
In numbers 1,2,3,4…..30 there are 5 perfect square number.
We know,
= /
Probability that a number selected a perfect square number = 5 / 30
Probability that a number selected a perfect square number = 1 / 6
21.) In a box of 600 electric bulbs, 15 bulbs are defective. One bulb is taken out at random. Find the probability that it is a non-defective bulb.
Answer:
Given that,
In a box of 600 electric bulbs, 15 bulbs are defective. One bulb is taken out at random.
We have to find probability that it is a non-defective bulb
Number of non-defective bulb = 600 – 15 = 585
We know,
= /
Probability that it is a non-defective bulb = 585 / 600
Probability that it is a non-defective bulb = 39 / 40
22.) The following pie chart shows the expenditure done by a family in different heads as percentage of its income. Answer the questions from 22 to 27.
On which item, the expenditure is double than the expenditure on rent?
The expenditure on rent is 15%
the expenditure is double than the expenditure on rent i.e. 30 % is of Education.
On Education the expenditure is double than the expenditure on rent.
23.) In which head, the expenditure is least?
Answer:
The expenditure is least on Entertainment i.e. 5%
24.) If expenditure on food items is Rs.5000, find the expenditure done by the family on entertainment.
Answer:
Given that,
Expenditure on food items is Rs.5000
We have to find expenditure done by the family on entertainment.
Expenditure on food is 20%
Expenditure on entertainment is 5%
20% = Rs. 5000
5% = ?
By cross multiplication,
Expenditure done by the family on entertainment = Rs. 1250
25.) What is the ratio of the amount spent on education to that on the others?
Answer:
We have to find ratio of the amount spent on education to that on the others.
On education there are 30% amount spent.
On others there are 10% amount spent.
Ratio of the amount spent on education to that on the others = 3:1
26.) Expenditure on which two heads are equal.
Answer:
Expenditure on which two heads are Transport and Food which is 20%
27.) Find the difference of expenditures done on education and transport, if the expenditure on rent is Rs. 4500.
Answer:
Given that, the expenditure on rent is Rs. 4500
We have to find the difference of expenditures done on education and transport.
The expenditure on rent is 15% = Rs. 4500
The difference of expenditures done on education and transport = 30 – 20 = 10 %
15% = Rs. 4500
10% = ?
By cross Multiplication,
The difference of expenditures done on education and transport = Rs.3000
In a school, a sports survey on 720 students shows the following results in the form of a Pie chart. Answer the questions from 28 to 33.
28.) Which is the least popular game in the school?
Answer:
Least popular game in the school is Lawn Tennis which is 10%,
29.) How many students do not like football?
Answer:
There are total 720 students.
Students who like football is 20%
Students who do not like football = 100 – 20 = 80%
720 x 80 / 100 = 576
Students who do not like football are 576.
30.) How many students play football and lawn tennis?
Answer:
Students who like football is 20%
And,
Students who like lawn Tennis is 10%
Total 30 % students play football and lawn tennis.
= 720 x 30 / 100 = 216
216 students play football and lawn tennis.
31.) Find the central angle made by cricket.
Answer:
We have to find central angle made by cricket.
Students who like cricket is 30%
= 720 x 30 / 100 = 216
Now, we know,
= / × °
= (216 / 720) × °
made by cricket =°
32.) How many students like either cricket or football?
Answer:
We calculate
Students who like cricket is 30%
= 720 x 30 / 100 = 216
Students who like football is 20%
= 720 x 20 / 100 = 144
Students like either cricket or football = 216 + 144
Students like either cricket or football = 360
33.) Find the number of students who like badminton.
Answer:
Students who like badminton is 15%
= 720 x 15 / 100 = 108
Students who like badminton are 108.
Study the given bar graph and answer the following questions from 34 to 36.
34.) For how many hours the least number of students watch T.V.
Answer:
From figure 1 hour the least number of students watch T.V.
35.) How many students watch T.V. less than 4 hours?
Answer:
34 students watch T.V. less than 4 hours.
36.) How many students spend more than 4 hours watching T.V.?
Answer:
14 students spend more than 4 hours watching T.V.
Study the given histogram and answer the following questions from 37 to 41.
37.) What is the class size?
Answer:
Class size of given graph is 10.
38.) How many students obtain less than 20 marks?
Answer:
From given graph,
Number of students obtain less than 20 marks = 3 + 6 = 9 Students
39.) How many students obtain 30 or more marks but less than 50?
Answer:
From given graph,
Number of studentsobtain 30 or more marks but less than 50 = 3 + 8 = 11 Students
40.) How many students got more than 60 marks?
Answer:
From given graph,
Number of students got more than 60 marks = 5 + 7 = 12 students.
41.) If the passing marks is 30, what is the number of failure students?
Answer:
From given graph,
If the passing marks is 30.
The number of failure students = 3 + 6 + 10 = 19 students.
The number of failure students is 19 students.
Study the given histogram and answer the following questions from 42 to 46.
42.) Tell the age group in which the number of literate females is the highest.
Answer:
From given graph,
The age group 15-20 has the number of literate females is the highest.
43.) What is the class width?
Answer:
Class width is difference between two bars in graph.
Class width of given graph is 5.
44.) What is the lowest frequency?
Answer:
The lowest frequency of given graph is 300.
45.) In which age group literate females are least?
Answer:
In age group10-15literate females are least.
46.) How many females are literate in the age group 20 to 30?
Answer:
From given graph,
Females are literate in the age group 20 to 30 = sum of age group 20-25 + 25-30
Females are literate in the age group 20 to 30 = 900 + 800 = 1700
In the age group 20 to 30, there are 1700females are literate.
The following histogram shows the frequency distribution of ages of 25 teachers in a school. Answer the following questions from 47 to 50.
47.) What is the number of teachers in the group 25 to 45?
Answer:
The number of teachers in the group 25 to 45 = Sum of age group of 25-30 + 30-35 + 35 -40 + 40 – 45
The number of teachers in the group 25 to 45 = 5 + 3 + 6 + 5 = 19
The number of teachers in the group 25 to 45 is 19
48.) Find the size of classes.
Answer:
Size or width of class is difference between two bars in graph.
25 – 20 = 5
Size of classes is 5.
49.) How many teachers are in the age group 40-45?
Answer:
Teachers are in the age group 40-45 is 5.
50.) How many teachers are in the age group 30-45?
Answer:
Teachers are in the age group 30-45 = Sum of age group 30-35 + 35-40 + 40-45
Teachers are in the age group 30-45 = 3 + 6 + 5 = 14
Teachers are in the age group 30-45 is 14.
Others Chapter Solution:
Chapter 1 |
Rational Numbers |
Chapter 2 | |
Chapter 3 |
Understanding Quadrilaterals |
Chapter 4 |