7th Standard CBSE Syllabus & Materials
7th Standard CBSE
CBSE 7th Social Science Theme E - Understanding Market - New Sample Question Papers Study Material - QB365 Set A
NEW7th Standard CBSE
CBSE 7th Social Science Theme E - From Barter to Money - New Sample Question Papers Study Material - QB365 Set A
NEW7th Standard CBSE
CBSE 7th Social Science Theme D - The Constitution of India- An Introduction - New Sample Question Papers Study Material - QB365 Set A
NEW7th Standard CBSE
CBSE 7th Social Science Theme D - From the Rulers to the Ruled : Types of Governments - New Sample Question Papers Study Material - QB365 Set A
NEW7th Standard CBSE
CBSE 7th Social Science Theme B - The Age of Reorganisation - New Sample Question Papers Study Material - QB365 Set A
NEW7th Standard CBSE
CBSE 7th Social Science Theme B - The Rise of Empires - New Sample Question Papers Study Material - QB365 Set A

Published on: 06/03/2020
7th Standard CBSE Mathematics Annual Exam Model Question 2020
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Questions + Answers key
Take MCQ Mathematics Test

1.
Express the following numbers in expanded forms:
5901
2.
Fill the correct symbol >, =, < in the following blanks.
(a) Faces of pyramid ----- Vertices of the pyramid.
(b) Faces of pyramid ----- Edge of the base
(c Edges on the base of a tetrahedron ------ Faces of a tetrahedron.
3.
Amisha has a square plot of side mand another triangular plot with base and height each equal to m. What is the total area of both plots?
4.
In the following figures, perimeter of \(\Delta\)ABC = perimeter of \(\Delta\)PQR. Find the area of \(\Delta\)ABC.

5.
Draw all the lines of symmetry for the following letters if they exist.

6.
The strength of a school is 2000. If 40% of the students are girls, then how many boys are there in the school?
7.
Construct ΔPQR, if PQ = 5 cm, mㄥPQR = 105° and mㄥQRP = 40°.
8.
In the following figure, find the value of \(\angle PQR\).

9.
Rajan is a fatty person. His weight is around 82 kg. He wants to lose his weight in 8 months. So regularly he goes for early morning exercise and take very balanced, diet after consulting to physician. After 8 months, Rajan's weight decreased by (\(\frac { 3 }{ 20 } \)) of his original weight (before 8 months). Find the current weight of Rajan. What type of value depict from Rajan?
10.
In the following figure, EF || GH, \(\angle\)EAB = 70° and \(\angle\)ACH=120°. Then, find \(\angle\)CAF and \(\angle\)BAC.

11.
Write five pairs of integers (a, b) such that a \(\div\) b = - 3. One such pair is (6, - 2) as 6 \(\div\) (-2) = (-3).
12.
Express each of the given statements as an equation.
(i) If 1 is subtracted from a number and the difference is multiplied by \(\frac{1}{2}\), the result is 7.
(ii) Mohan is 3 yr older than Sohan. The sum of their ages is 43 yr.
(iii) Five times a number increased by 7 is 27.
13.
Vipin, a Class VII student received cash award of Rs. 5000 in the singing competition. His father advised him to made a budget plan for spending this amount. He made following plan:
| S.no | Head | Amount |
|---|---|---|
| 1 | Donation in temple | 150 |
| 2 | Tuition fee to needy child | 200 |
| 3 | Welfare of senior citizens | 300 |
| 4 | Welfare of street children | 300 |
| 5 | Saving in bank | 1500 |
| 6 | Books for family library | 500 |
| 7 | Picnic for family | 650 |
| 8 | Gift to grand parents | 600 |
| 9 | Tea party to friends | 800 |
| Total | 5000 | |
Make a bar graph for the above data,
(i) find the mode and median of above distribution of money,
(ii) which values are depicted in his plan?
14.
Which of the following pair of figures are congruent?

15.
Michael finished colouring a picture in \(\frac{7}{12}\) hr.Vaibhav finished colouring the same picture in \(\frac{3}{4}\)hr.Who worked longer? By what fraction was it longer?
16.
Mahesh takes a loan of Rs.50,000 at The rate of interest 12% p. a. Find the simple interest, which he has to pay after two years.
17.
Construct an obtuse angled triangle, which has a base of 5.5 cm and base angles of 30° and 120°.
18.
If a cone is cut from the top horizontally, then which 2-D figure will be seen?
19.
Simplify and write in exponential form: 25 x 23
20.
The distance of a 24 cm long side of a parallelogram from the opposite side is 22 cm. Then, find the area of the parallelogram.
21.
Given the line(s) of symmetry, find the other hole(s).

22.
Express as rupees using decimals. 7 rupees 7 paise
23.
Identify terms and factors in the expressions given below. 1.2ab - 2.4b + 3.6a
24.
State whether the following triangle exists.

25.
Find (-100) \(\div\) 5
26.
In the following figure, find the value of x.

27.
Solve the equation 3 (2x + 1) = 6.
28.
In the given figures, measures of some parts of triangles are given. By applying RHS congruence rule, state which pairs of triangles are congruent? In case of congruent triangles, write the result in symbolic form.

29.
The median of the following observations arranged in ascending order is 24. Find the value of x. 11,12,14,18,(x+2),(x+4),30,32,35,41
30.
Divide the difference of \(\frac { 2 }{ 5 } \) and \(\frac { 3 }{ 13 } \) by the product \(\frac { 2 }{ 9 } \) and \(\frac { 3 }{ 5 } \)
31.
If Ramesh has 5x2 + 3x - 2 rupees and Mahesh has x2 - x + 5 rupees. If both of them deposited the money in same account, and withdrawal a sum of rupees 2x2 - x - 3.
(a) What is the balance of amount in their account.
(b) Which mathematical concept is used in this problem?
(c) Whatis its value?
32.
Draw a line 1. Draw a perpendicular to 1 at any point on 1. On this perpendicular AB take any point X, 3 em away from 1. Through X, draw a line m parallel to 1.
33.
If a father gave 3 parts of his property to his son and 2 parts of it to his daughter. What are the percentages of his property which were given to his son and daughter?
34.
Fill in the box with correct symbol out >,< and =.
\(\frac { -7 }{ 8 } \boxed { } \frac { 14 }{ -16 } \)
35.
Express each of the following numbers using exponential notations.
1024
36.
Given the line of symmetry, find the other hole.

37.
Make a net for given cone
38.
In her Science class, Jyoti learnt that the atomic weight of Helium is 4.0030, of Hydrogen is 1.0080 and of Oxygen is 16.0000. Find the difference between the atomic weights of Oxygen and Helium.
39.
Through a rectangular field of length 90 m and breadth 60 m, two roads are constructed which are parallel to the sides and cut each other at right angles through the centre of the fields. If the width of each road is 3 m, find
(i) the area covered by the roads.
(ii) the cost of constructing the roads at the rate of Rs 110 per m2.
40.
In the following figures, lengths of the sides of the triangles are indicated. By applying SSS congruence rule, state which pairs of triangles are congruent? In case of congruent triangles, write the result in symbolic form.

41.
Riya walks 6 km due East and then 8 km due North. How far is she from her starting place?
42.
A certain freezing process requires that room temperature be lowered from 30°C at the rate of 5°C every hour. What will be the room temperature 12 h after the process begins?
43.
Radha got Rs 17480 as her monthly salary and overtime. Her salary exceeds the over-time by Rs 10000. What is her monthly salary?
44.
The bar graph given below shows the marks of students of a class in a particular subject

How many students scored 90 marks and above?
45.
In the given figure, if \(\angle \) 1=30°, find \(\angle \) 2 and \(\angle \) 3.

46.
What should be subtracted from x2 + y2 - 2xy to get x2 + y2?
2xy
-2xy
xy
-xy
47.
The exponential form of 1000 is
101
102
103
104
48.
The area of a square plot is 1600 m2. The side of the plot is
40 m
80 m
120 m
160 m
49.
In the following figure, \(\angle AOB\) and \(\angle BOC\) are

complementary angles
supplementary angles
adjacent angles
none of these
50.
For two given triangles ABC and PQR, how many matchings are possible?
2
4
6
3
51.
If two sides of a triangle are equal, the triangle is called
isosceles
equilateral
scalene
right-angled.
52.
When two positive integers are added, we get
a positive integer
a negative integer
sometimes a positive integer, sometimes a negative integer
none of these
53.
Read the following bar graph and answer the question
The difference between maximum and minimum marks is
100
200
400
500
54.
Adjoining figure is:

cone
Square pyramid
Prism
Triangular pyramid
55.
If x - 5 = 2, then x is equal to
7
3
-3
\(\frac{2}{5}\)
56.
\(\frac { 3 }{ 7 } \) of \(\frac { 2 }{ 5 } \)is equal to
\(\frac { 5 }{ 12 } \)
\(\frac { 5 }{ 35} \)
\(\frac { 1 }{ 35} \)
\(\frac { 6 }{ 35} \)
57.
Which of the following is equivalent to \(\frac{4}{5}\)?
\(\frac{5}{4}\)
\(\frac{16}{25}\)
\(\frac{16}{20}\)
\(\frac{15}{25}\)
58.
Which of the following is the ratio of 3 km to 300 m?
10:1
1:10
100:1
1:100
59.
Which of the following letters of English alphabets have more than 2 lines of symmetry?
Z
O
E
H
60.
A triangle can be constructed by taking its sides as.
1.8 cm, 2.6 cm, 4.4 cm
2 cm, 3 cm, 4 cm
2.4 cm, 2.4 cm, 6.4 cm
3.2 cm, 2.3 cm, 5.5 cm
61.
Find angles x and y in each figure.

62.
The circumference of two circles are in the ratio 5 : 6. Find the ratio of their areas.
63.
The mean marks (out of 100) of a group of students is 60. If their marks are 85, 62, 36, 48, 72, x, 75 and 39, then find the value of x.
64.
If A = 2a - 3b, B = - 3a + 4b and C = - a + b, find A + B + C and A + B - C.
65.
By what number should (-15)-1 be divided so that the quotient is (-5)-1.
66.
How much pure alcohol must be added to 400 ml of a 15% solution to make its strength 32%.
67.
Nikhil's income is 20% less than that of Akhil. How much percent is Akhil's income more than that of Nikhil's?
68.
Arrange the rational numbers \(\frac { -3 }{ 5 } ,\frac { 7 }{ -10 } ,\frac { -5 }{ 6 } \\ \) ascending order.
69.
Two poles of height 9 m and 14m stand upright on a plane ground. If the distance between their tops is 13 m, find the distance between their feets.
1.
5 X 103 + 9 X 102+ 0 x 101 + 1 x 100
2.
(a) = (b) > (b) <
3.
Given, side of square plot = m
Triangular plot has base and height = m
Now, Area of square plot = (Side)2 = m2
Area of triangular plot = \(\frac { 1 }{ 2 } \)x base x height
= \(\frac { 1 }{ 2 } \) x m xm = \(\frac { { m }^{ 2 } }{ 2 } \)
\(\therefore\) Total area of both plots
= Area of square plot + Area of triangular plot
= \({ m }^{ 2 }+\frac { { m }^{ 2 } }{ 2 } =\frac { 2{ m }^{ 2 }+{ m }^{ 2 } }{ 2 } =\frac { { 3m }^{ 2 } }{ 2 } \)
4.
Given, perimeter of \(\Delta\)ABC = perimeter of \(\Delta\)POR
So, perimeter of \(\Delta\)POR = 14 + 6 + 10 = 30 cm
Now, perimeter of \(\Delta\)ABC,
30 = AB + BC + AC \(\Rightarrow\) 30 = AB + 5 + 13
\(\Rightarrow\) 30 = AB + 18 \(\Rightarrow\) AB = 30 - 18 = 12
\(\therefore\) Area of the \(\Delta\)ABC = \(\frac{1}{2}\) x Base x Height
= \(\frac{1}{2}\) x 5 x 12 = 5 x 6 = 30 cm2.
5.

6.
As per the given information in the question,
the strength of school = 2000
Percentage of girls in school = 40%
Percentage of boys in school = 100% - 40% = 60%
Number of boys in school =\({60\over100}\times 2000\)
= 60 x 20 = 1200
Hence, number of boys in school is 1200.
7.
Given, PQ = 5 cm, mㄥPQR = 105° and m ㄥQRP = 40°
In ΔPQR, by angle sum property, we have
ㄥPQR + ㄥQRP + ㄥRPQ = 180°
⇒ 105° + 40° + ㄥRPQ = 180°
⇒ ㄥRPQ = 180° -145° = 35°
Thus, we have PQ = 5 cm, ⇒ ⇒P = 35° and ⇒Q = 105°
Now, to draw ΔPQR, we use the following steps:
Steps of construction
Step I Firstly, we draw a rough sketch of traingle with measures marked on it.

Step II Draw a line segment PQ = 5 cm.

Step III At point P, draw a ray PX making an angle of 350 with PQ i.e., ㄥQPX = 350.

Step IV At point Q, draw a ray QY making an angle of 105° with PQ i.e. ㄥPQY = 105°.

Step V Extend the ray PX and QY. Let rays PX and QY intersect at R.

Thus, ΔPQR is the required triangle.
8.
1290
9.
Rajan's weight 8 months ago was 82 kg. After regular schedule and exercise his weight reduced to \(\frac { 3 }{ 20 } \) of his original weight.
Reduced weight = \(\frac { 3 }{ 20 } \) \(\times \) 82
= 3\(\times \) 4.1=12.3Kg
=12 kg and 300g
New weight =82-12.3kg=69.7kg
=69 kg and 700g
The value depicted from Rajan is that he properly follows the physician's diet chart and do exercise regularly. So Rajan's is very conscious about his physical fitness.
10.
Since, lines EF and GH are parallel to each other.
Where, \(\angle\)EAB = 70° and \(\angle\)ACH =120°
\(\angle\)EAB and \(\angle\)CBA are alternate angles.
So, \(\angle\)CBA = 70°
\(\because\) (\(\angle\)EAB + \(\angle\)BAC) and \(\angle\)ACH are alternate angles.
so, \(\angle\)EAB + \(\angle\)BAC = 120°
\(\Rightarrow\) 70° + \(\angle\)BAC =120°
\(\angle\)BAC =120° \(\Rightarrow\)-70° = 50°
\(\because\)\(\angle\)CAE = \(\angle\)EAB + \(\angle\)BAC
\(\therefore\) \(\angle\)CAE = 70° + 50° = 120°
Also, \(\angle\)FAC + \(\angle\)CAE =180°
\(\Rightarrow\)\(\angle\)FAC = 180° -120°
\(\therefore\) \(\angle\)FAC = 60°
11.
(i) We know that, 3 \(\div\) 1= 3, so 3 \(\div\) (- 1)= - 3
On comparing with a \(\div\) b = - 3, we get a = 3 and b = -1
Hence, the required pair of integers is (3, -1).
(ii) We know that, 12 \(\div\) 4 = 3, so 12 \(\div\)(- 4) = - 3
On comparing with a \(\div\) b = - 3, we get a = 12 and b = -4
Hence, the required pair of integers is (12, - 4).
(iii) We know that, 9 \(\div\) 3 = 3, so 9 \(\div\) (- 3) = - 3
On comparing with a \(\div\) b = - 3, we get a = 9 and b = -3
Hence, the required pair of integers is (9, - 3).
(iv) We know that,12 \(\div\) 4 = 3, so (-12) \(\div\) 4 = -3
On comparing with a \(\div\) b = - 3, we get a = -12 and b=4
Hence, the required pair of integers is (-12, 4).
(v) We know that, 15 \(\div\) 5 = 3, so 15 + (- 5) = -3
On comparing with a \(\div\) b = - 3, we get a = 15 and b = -5
Hence, the required pair of integers is (15, - 5).
12.
(i) Let the number be x.
Now, 1 is subtracted from a number, then
(x -1), the difference is multiplied by \(\frac{1}{2}\)
Here, \(\frac{1}{2}\) (x - 1) gives result 7
\(\therefore \frac{1}{2}(x-1)=7\)
(ii) Let age of Soh an be x yr. Then, the age of
Mohan is (x + 3) yr.
\(\therefore\) Sum of their ages = 43
\(\Rightarrow\) x+(x+ 3)=43
(iii) Let the number be x. Then, five times of number be 5x.
Since it is increased by 7.
So, 5x + 7 gives result 27.
Hence, the equation is 5x + 7 = 27.
13.

(i) Mode = Heighest frequency observation = 300
For median, we have to arrange the data in ascending order, 150,200,300,300,500,600, 650, 800, 1500
Median = 500
(ii) Value He is very socialised student and also
very kind towards his socities.
14.
Not congruent
15.
Time taken by Michael to finished colouring the picture \(\frac{7}{12}\)hr
Time taken by Vaibhav to finished colouring the picture = \(\frac{3}{4}\)hr

LCM of 12 and 4 = 3 X 4 = 12
On converting these fractions into like fractions, we get
\(\frac{3}{4}=\frac{3\times 3}{4\times 3}=\frac{9}{12} and \frac{7}{12}=\frac{7}{12}\)
It is clear, 9>7 [numerators of fractions]
So, \(\frac{9}{12}>\frac{7}{12} i.e., \frac{3}{4}>\frac{7}{12}\)
So, Vaibhav takes longer time to finish colouring the picture. Difference between time taken by Vaibhav and Michael
\(=\frac{3}{4}-\frac{7}{12}\)

LCM of 4 and 12 = 2 x 2 x3 = 12
\(=\frac{3}{4}-\frac{7}{12}=\frac{3\times 3-7\times 1}{12}\)
=\(\frac{9-7}{12}=\frac{2}{12}=\frac{1}{6}\) [dividing numerator and denominator by 2]
Hence, Vaibhav takes \(\frac{1}{6}\) h more than Michael.
16.
\(S.I=\frac { P\times R\times T }{ 100 } \)
\(=\frac { 50,000\times 12\times 2 }{ 100 } \)
S.I =Rs.12,000
17.

18.
Circle
19.
25 x 23 = 25+3 = 28
20.
528 cm2
21.
With respect to the given line(s) of symmetry, the other hole(s) are marked in the figures given below:

22.
We have, 7 rupees 7 paise = 7 rupees + 7 paise
=\(7+\frac{7}{100}\)=7+0.07=7.07 [∵ 1 paise= Rs \(\frac{1}{100}\)]
23.
In the expression 1.2ab - 2.4b + 3.6 a, terms are 1.2ab, -2.4b and 3.6a and factors of l.2ab are 1.2, a, b, factors of -2.4b are -2.4, b and factors of 3.6a are 3.6, a.
24.
No, the given triangle does not exist, since it doesn't satisfy the triangle inequality.
In the given \(\triangle ABC\)
\(\overline{AB}=24cm,\overline{AC}=12cm,\overline{BC}=11cm\)
Now \(\overline{AC}+\overline{BC}=12+11=23\) and \(\overline{AB}=24cm\)
\(\therefore \overline {AC}+\overline{BC}<\overline{AB}.\) Hence, the required triangle doesn't exist.
25.
We have, (-100) \(\div\) 5 = - (100 \(\div\) 5) = -100/5 = -20
26.
x=40°
27.
Given, equation 3(2x + 1) = 6
Dividing both sides by 3, we get
\((2x+1)=\frac{6}{3}\Rightarrow\) 2x + 1 = 2
2x = 2 - 1 \(\Rightarrow\) 2x = 1 \(\Rightarrow\) x = \(\frac{1}{2}\)
\(\therefore x=\frac{1}{2}\) is the required solution.
28.
In ΔCAB and ΔDAB, ㄥC = ㄥD = 90°
Hypotenuse AB = Hypotenuse AB [common]
CA= DB= 2 cm
So, both triangles are congruent by RHS congruence rule.
The correspondence is A ↔️ B, C ↔️ D, B ↔️ A.
In symbolic form, ΔACB ≅ ΔBDA
29.
x = 21
30.
\(\frac { 75 }{ 182 } \)
31.
(a)Total amount deposited in account = (5x2 + 3x-2) + (x2-x + 5)
=5x2 + 3x-2+ x2-x + 5
=5x2 + x2+ 3x-x-2+ 5
=6x2+2x+3
Balance amount
= (6x2+2x+3)-(2x2-x-3)
= 6x2+2x+3-2x2-x-3
= 6x2-2x2+ 2x + x + 3 + 3
=4x2+3x+6.
(b) Addition of algebraic expressions.
(c) Value: Economy is everywhere.
32.
Steps of Construction:
(a) Draw a line I and mark a point A on it.
(b) Construct an angle of 90° at A to draw AB perpendicular at l.
(c) Mark a point X on AB such that AX = 3 cm.
(d) At X, construct an angle of 90° to draw a perpendicular to AB. Thus, 'm' is the required line through X such that m II l.
33.
Total of parts = 3 + 2 = 5
\(\Rightarrow \) Son got = \(\frac { 3 }{ 5 } \)part
\(\Rightarrow \) So his percentage share =\(\frac { 3 }{ 5 } \)X 100=60%
His daughter got=\(\frac { 2 }{ 5 } \) part
So, her percentage share =\(\frac { 2 }{ 5 } \)X100=40%
34.
Given,\(\frac { -7 }{ 8 } \boxed { } \frac { 14 }{ -16 } \) or \(\frac { -7 }{ 8 } \boxed { } \frac { 14\times (-1) }{ -16\times (-1) } \) or \(\frac { -7 }{ 8 } \boxed { } \frac { -14 }{ 16 } \)
Here, both rational numbers are negative.
On ignoring the negative sign, we have \(\frac { 7 }{ 8 } \) and \(\frac { 14 }{ 16 } \).
Now, Converting these rational numbers into the
rational numbers having same denominator, we get
\(\frac { 7 }{ 8 } =\frac { 7\times 2 }{ 8\times 2 } =\frac { 14 }{ 16 } \) and \(\frac { 14 }{ 16 } =\frac { 14 }{ 16 } \) [ multiplying the numerator and denominator by 2]
Since, 14=14
\(\\ \therefore \frac { 14 }{ 16 } =\frac { 14 }{ 16 } \Rightarrow \frac { 7 }{ 8 } =\frac { 14 }{ 16 } \)
\(\Rightarrow \frac { -7 }{ 8 } =\frac { -14 }{ 16 } \Rightarrow \frac { -7 }{ 8 } =\frac { 14 }{ -16 } \)
Hence, \(\frac { -7 }{ 8 } =\frac { 14 }{ -16 } \)
35.
Given, 1024
∵ 1024 = 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 = 210

The exponent form of 1024 is 210.
36.

37.
Net for the given cone figure will be
38.
Given, atomic weight of Helium = 4.0030, Hydrogen = 1.0080 and Oxygen = 16.0000
Difference between atomic weights of Oxygen and Helium
16.0000
-04.0030
________
11.9970
________
39.
Let ABCD represents the rectangular field of length AB = 90 m and breadth AD = 60 m. Area of shaded portion i.e. area of the rectangle PQRS and the area of rectangle EFGH represents the area of crossroads, but here the area of square KIMN is taken twice, so it will be subtracted.
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Now, PQ = 3 m, PS = 60 m, EH = 3 m, EF = 90 m, KL = 3 m and KN = 3 m
(i) Area covered by the road = Area of rectangle PQRS + Area of rectangle EFGH - Area of square KIMN
= PQ x PS + EH x EF - (KL)2
= 3 x 60 + 3 x 90 - 3 x 3 = 180 + 270 - 9 = 441 m2
(ii) Cost of constructing 1 m2 road = Rs 110
\(\therefore\) Cost of constructing 441 m2 road
= Rs (441 x 110) = Rs 48510
Hence, the cost of constructing the road is Rs 48510.
40.
In ΔABD and ΔADC, we have
AB= AC =35 cm, BD= DC = 25 cm and AD = AD [common]
Therefore, the three sides of MBD are equal to three sides of ΔADC.
So, two triangles are congruent by SSS congruence rule.
From the above equality relations, we have
A ↔️ A, B ↔️ C, and D ↔️ D
In symbolic form, ΔABD ≅ ΔACD
41.
As per the given information, we can draw the following figure, which is a right angled triangle at B.

Distance from starting point is the hypotenuse of \(\triangle ABC\),
(6)2 +(8)2 = (Distance)2
\(\Rightarrow\) 36 + 64 = (Distance)2
\(\therefore\ Distance=\sqrt 100=10 km\)
42.
As per the given information in the question,
Room temperature = 30° C
Change in temperature per hour = - 5° C
Change in temperature in 12 h = 12 x (-5) = - 60° C
Room temperature after 12 h = 30° C + ( - 60° C)
= -30°C
43.
Radha's monthly salary and overtime = Rs 17480
Let x be the monthly salary.
Then, over-time = Rs (x -10000)
\(\therefore\) 17480 - x = x -10000
2x = 27480 \(\Rightarrow\) x=13740
Hence, her monthly salary is Rs 13740.
44.
From the bar graph, we can see students which scored marks above 90 are in the range of 90-92. Hence, 4 students scored above 90 marks
45.
Given, \(\angle \)1= 30°
Since, \(\angle \)1 and \(\angle \)2 form a linear pair.
\(\therefore\) \(\angle \)1+ \(\angle \)2 = 180° \(\Rightarrow\) 30° + \(\angle \)2 = 180°
[transposing 30° to RHS]
\(\Rightarrow\) \(\angle \)2 = 180° - 30°\(\Rightarrow\) \(\angle \) 2 = 150°
Now, \(\angle \)3 = \(\angle \)1= 30° [vertically opposite angles]
Hence, \(\angle \)2 = 150° and \(\angle \)3 = 30°
46.
(b)
-2xy
47.
1000 = 10 x 10 x 10 = 103
48.
Side =\(\sqrt { 1600 } \)=40 m
49.
(d)
none of these
50.
ABC ↔️ PQR, ABC ↔️ PRQ,
ABC ↔️ QRP, ABC ↔️ QPR,
ABC ↔️ RPQ, ABC ↔️ RQP.
51.
Definition of an isosceles triangle.
52.
(a)
a positive integer
53.
600 -100 = 500
54.
(d)
Triangular pyramid
55.
56.
(d)
\(\frac { 6 }{ 35} \)
57.
(c)
\(\frac{16}{20}\)
58.
(a)
10:1
59.
(b)
O
60.
(b)
2 cm, 3 cm, 4 cm
61.
(i) x + y = 1200 ...(1)
The exterior angle of a triangle is equal to the sum of its two interior opposite angles
x + y + y = 1800
Base angles opposite to the equal sides of an isosceles triangle are equal and the sum of the measures of the three angles of a triangle is 1800
\(\Rightarrow\)x + 2y = 1800 ... (2)
Subtracting equation (1) from equation (2),
y = 60°
Put y = 60° in equation (1),
x + 60° = 120°
\(\Rightarrow\)x = 120° - 60°
\(\Rightarrow\)x = 60°
62.
Let the radii of the given circles be r1 and r2. Let their circumference be 'C1' and 'C2' respectively.
\(\therefore\)C1 = 2\(\pi\)r1 and C2 = 2\(\pi\)r2
Since, C1 : C2 = 5 : 6
\(\therefore\)(2\(\pi\)r1):(2\(\pi\)r2)=5:6
\(\Rightarrow\)\(\frac { 2\pi r_{ 1 } }{ 2\pi r_{ 2 } } =\frac { 5 }{ 6 } \Rightarrow \frac { { r }_{ 1 } }{ { r }_{ 2 } } =\frac { 5 }{ 6 } \)
Now, let the area of the given circles be A1 and A2
\(\therefore\)A1 = \(\pi\)r12 and A2 = \(\pi\)r22
\(\Rightarrow\)\(\frac { { A }_{ 1 } }{ A_{ 2 } } =\frac { { { \pi r }_{ 1 } }^{ 2 } }{ { { \pi r }_{ 2 } }^{ 2 } } =\frac { { { r }_{ 1 } }^{ 2 } }{ { { r }_{ 2 } }^{ 2 } } \Rightarrow \frac { A_{ 1 } }{ A_{ 2 } } =\left( \frac { { { r }_{ 1 } } }{ { { r }_{ 2 } } } \right) ^{ 2 }\)
\(\Rightarrow\)\(\frac { { A }_{ 1 } }{ A_{ 2 } } =\left( \frac { 5 }{ 6 } \right) ^{ 2 }=\frac { 25 }{ 36 } \Rightarrow \)A1:A2
= 25:36
Thus, the areas of the two given circles are in the ratio 25 : 36.
63.
Total number of students = 8
Sum of the marks obtained =85 + 62 + 36 + 48 + x + 75 + 39 + 72=417+x
\(\therefore \)Mean marks =\(\frac { (417\quad +x) }{ 8 } \)
\(\Rightarrow \)\(\frac { (417\quad +x) }{ 8 } \)=60
\(\Rightarrow \)417 + x = 60 x 8 = 480
\(\Rightarrow \)x = 480 - 417 = 63
Thus, the required value of x = 63
64.
A = 2a - 3b
B=-3a+4b
C = -a + b
A+B+C=?
A + B + C = (2a-3b) + (-3a + 4b) + (-a + b)
= 2a-3b-3a + 4b-a + b
= a(2 - 3 -1) + b(- 3 + 4 + 1)
= a(2 - 4) + b(1 + 1)
=-2a+2b
A+B-C=?
A + B - C = (2a- 3b) + (- 3a + 4b) - (- a + b)
= 2a-3b-3a + 4b + a-b
= a(2-3 + 1) + b(-3 + 4-1)
= a(0) + b(-4 + 4)
= a(0) + b(0)
= 0.
65.
Let the number (- 15)-1 should be divided by x to get the quotient (-5)-1.
\(\therefore (-15)^{-1}\div x=(-5)^{-1}\)
\(\Rightarrow \frac{1}{-15}\div x=\frac{1}{-5}\)
\(\Rightarrow \frac{1}{-15}\times \frac{1}{x}=\frac{1}{-5}\)
\(\Rightarrow \frac{1}{-15x}=\frac{1}{-5}\)
\(\Rightarrow -15x\times 1=-5\times 1\)
\(\Rightarrow -15x = -5\)
\(\Rightarrow x=-\frac{5}{-15}\)
\(\Rightarrow x=-\frac{1}{-3}\)
\(\Rightarrow x=\frac{1}{3}\)
66.
Quantity of pure alcohol in 400 ml. of 15% = 400 \(\times \frac { 15 }{ 100 } \)
= 60 ml
Now, we add x ml of pure alcohol to the sample.
So, total pure alcohol = (60 + x) ml.
But volume of new sample = (400 + x) ml.
\(\therefore\) Percentage of pure alcohol in new sample \(=\frac { (60+x) }{ (400+x) } \times 100\)
which is equal to 32%
\(\Rightarrow \quad \frac { 60+x }{ 400+x } \times 100=32\)
\(\Rightarrow \quad \frac { 60+x }{ 400+x } =\frac { 32 }{ 100 } \)
\(\Rightarrow\) 100(60 + x) = 32 (400 + x)
\(\Rightarrow\) 100x + 6000 = 32x + 12800
\(\Rightarrow\) 100x-32x = 12800 - 6000
\(\Rightarrow\) 68x = 6800
\(\Rightarrow \ x=\frac { 6800 }{ 68 } =100\ ml\)
67.
Let Akhil's income be Rs.100
\(\Rightarrow \) Nikhil's income = 100 - 20
=Rs.80
Now Nikhil's income be Rs.80
\(\Rightarrow \)Akhil's income is Rs.20 more than that of Nikhil
\(\because \)When Nikhil's income is Rs.80. than Akhil's income is Rs.20 more
When Nikhil's income is Rs.100, then Akhil's income
=\(\frac { 20 }{ 80 } \times \)100
= 25% more
Hence Akhil's income is 25% more than Nikhil's income.
68.
Sequence is \(\frac { -3 }{ 5 } ,\frac { 7 }{ -10 } ,\frac { -5 }{ 6 } \\ \)
L.C.M.of 5, 10 and 6=30
\(\Rightarrow \frac { -3 }{ 5 } ,\frac { 7 }{ -10 } ,\frac { -5 }{ 6 } \)
\(\Rightarrow -\frac { 3\times 6 }{ 5\times 6 } ,\frac { 7\times 3 }{ -10\times 3 } ,-\frac { 5\times 5 }{ 6\times 5 } \)
\(\Rightarrow -\frac { 18 }{ 30 } ,\frac { 21 }{ 30 } ,\frac { 25 }{ 30 } \)
Since \(-\frac { 25 }{ 30 } <\frac { 7 }{ -10 } <\frac { -3 }{ 5 } \)
Hence sequence in ascending order is
\(\frac { -5 }{ 6 } <\frac { 7 }{ -10 } <\frac { -3 }{ 5 } \).
69.
In the above figure, AB and CD are two poles whose heights are 9 m and 14m respectively.
\(\Rightarrow\) AB = EC = 9m
and BD = 13m
DE = 14 - 9
= 5m
Now in right ΔBDE, by Pythagoras
BD2 = BE2 + DE2
132 = BE2 + 52
\(\Rightarrow\) BE2 = (13)2 - (5)2
= 169-25
BE2 = 144
\(\Rightarrow\) BE = \(\sqrt { 144 } \)
\(\Rightarrow\) BE = 12m.
Hence, distance between their feet = 12 m.
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