NCERT Class 7 Maths Chapter 4 Simple Equations Exercise 4.4

Chapter 4 Simple Equations Exercise 4.4

Question 1: Set up equations and solve them to find the unknown numbers in the following cases:
(a) Add 4 to eight times a number; you get 60.
Answer:

= 8x + 4 = 60
= 8x = 60 - 4
= 8x = 56
= x = 56/8
= x = 7

(b) One-fifth of a number minus 4 gives 3.
Answer:
= x/5 - 4 = 3
= x/5 = 3 + 4
= x/5 = 7
= x = 7 × 5
= x = 35

(c) If I take three-fourths of a number and add 3 to it, I get 21.
Answer:

= 3/4 y + 3 = 21
= 3y/4 = 21 - 3
= 3y/4 = 18
= 3y = 18 × 4
= 3y = 72
= y = 72/3
= y = 24

(d) When I subtracted 11 from twice a number, the result was 15.
Answer:

= 2m - 11 = 15
= 2m = 15 + 11
= 2m = 26
= m = 26/2
= m = 13

(e) Munna subtracts thrice the number of notebooks he has from 50, he finds the result to be 8.
Answer:

= 50 - 3x = 8
= -3x = 8 - 50
= -3x = -42
= x = -42/-3
= x = 14

(f) Ibenhal thinks of a number. If she adds 19 to it and divides the sum by 5, she will get 8.
Answer:

= x + 19/5 = 8
= x + 19 = 8 × 5
= x + 19 = 40
= x = 40 - 19
= x = 21

(g) Anwar thinks of a number. If he takes away 7 from 5/2 of the number, the result is 23.
Answer:

= 5n/2 - 7 = 23
= 5n/2 = 23 + 7
= 5n/2 = 30
= 5n = 30 × 2
= 5n = 60
= n = 60/5
= n = 12

Question 2: Solve the following:
(a) The teacher tells the class that the highest marks obtained by a student in her class is twice the lowest marks plus 7. The highest score is 87. What is the lowest score?
Answer:

Let the lowest score be x.
Highest score is = 87
Highest score = 2x + 7
= 2x + 7 = 87
= 2x = 87 - 7
= 2x = 80
= x = 80/2
= x = 40
Therefore, the lowest score is 40.

(b) In an isosceles triangle, the base angles are equal. The vertex angle is 40°.
What are the base angles of the triangle? (Remember, the sum of three angles of a triangle is 180°).
Answer:

The sum of angles of a triangle = 180°
Let base angle be b.
= b + b + 40° = 180°
= 2b + 40° = 180°
= 2b = 180° - 40°
= 2b = 140°
= b = 140/2
= b = 70°
Therefore, 70° is the base angle of an isosceles triangle.

(c) Sachin scored twice as many runs as Rahul. Together, their runs fell two short of a double century. How many runs did each one score?
Answer:

Let Rahul’s score be x.
Sachin’s score = 2x
= Rahul’s score + Sachin’s score = 200 - 2
= x + 2x = 198
= 3x = 198
= x = 198/3
= x = 66
Rahul’s score = x = 66
Sachin’s score = 2x = 66 × 2 = 132
Therefore, Rahul’s score is 66 while Sachin’s score is 132.

Question 3: Solve the following:
(i) Irfan says that he has 7 marbles more than five times the marbles Parmit has. Irfan has 37 marbles. How many marbles does Parmit have?
Answer:

Let Parmit’s marbles be x.
Irfan’s marbles = 5x + 7
= 5x + 7 = 37
= 5x = 37 - 7
= 5x = 30
= x = 30/5
= x = 6
Therefore, Parmit has 6 marbles.

(ii) Laxmi’s father is 49 years old. He is 4 years older than three times Laxmi’s age. What is Laxmi’s age?
Answer:

Let Laxmi’s age be y years.
Laxmi’s father age = 3y + 4
= 3y + 4 = 49
= 3y = 49 - 4
= 3y = 45
= y = 45/3
= y = 15
Therefore, Laxmi’s age is 15 years.

(iii) People of Sundargram planted trees in the village garden. Some of the trees were fruit trees. The number of non-fruit trees were two more than three times the number of fruit trees. What was the number of fruit trees planted if the number of non-fruit trees planted was 77?
Answer:

Let the number of fruit trees be x.
Non fruit trees = 3x + 2
= 3x + 2 = 77
= 3x = 77 - 2
= 3x = 75
= x = 75/3
= x = 25
Therefore, number of fruit tree was 25.

Question 4: Solve the following riddle:
I am a number,
Tell my identity!
Take me seven times over
And add a fifty!
To reach a triple century
You still need forty!
Answer:

Let the number be x.
= 7x + 90 = 300
= 7x = 300 - 90
= 7x = 210
= x = 210/7
= x = 30
Therefore, the number is 30.

No comments:

Post a Comment

Buy from our Store

Visit our VS Store to get Extra Discounts! Only for our Beloved users!

Visit here

Also read!

• Class 6

Class 6 Computer Kips Solutions
Class 6 Gul Mohar English Solutions
→ Class 6 Map Pointing Solutions
Class 6 NCERT Civics Solutions
Class 6 NCERT Geography Solutions
Class 6 NCERT History Solutions
Class 6 NCERT Maths Solutions
Class 6 NCERT Science Solutions

• Class 7

Class 7 Computer Kips Solutions
Class 7 Gul Mohar English Solutions
English Grammar Class 7
English Writing Skills Class 7
Class 7 Map Pointing Solutions
Class 7 NCERT Civics Solutions
Class 7 NCERT Civics Notes
Class 7 NCERT Civics Extra Questions
Class 7 NCERT Geography Solutions
Class 7 NCERT Geography Notes
Class 7 NCERT Geography Extra Questions
Class 7 NCERT History Solutions
Class 7 NCERT History Notes
Class 7 NCERT History Extra Questions
Class 7 NCERT Maths Solutions
Class 7 NCERT Science Solutions
Class 7 NCERT Science Notes
Class 7 NCERT Science Extra Questions

• Class 8

Class 8 Kips Artificial Intelligence Solutions
Class 8 Gul Mohar English Solutions
English Grammar Class 8
English Writing Skills Class 8
Class 8 Map Pointing Solutions
Class 8 NCERT Civics Solutions
Class 8 NCERT Civics Notes
Class 8 NCERT Civics Extra Questions
Class 8 NCERT Geography Solutions
Class 8 NCERT Geography Notes
Class 8 NCERT Geography Extra Questions
Class 8 NCERT History Solutions
Class 8 NCERT History Notes
Class 8 NCERT History Extra Questions
Class 8 NCERT Maths Solutions
Class 8 NCERT Science Solutions
Class 8 NCERT Science Notes
Class 8 NCERT Science Extra Questions
Class 8 NCERT Science Exemplar
Class 8 NCERT Science MCQs

• Class 9

Class 9 Kips Artificial Intelligence Solutions
Class 9 Map Pointing Solutions
Class 9 NCERT Civics Solutions
Class 9 NCERT Geography Solutions
Class 9 NCERT History Solutions
Class 9 NCERT Maths Solutions
Class 9 NCERT Science Solutions

• Class 10

Class 10 Kips Artificial Intelligence Solutions
Class 10 NCERT English Solutions
→ Class 10 Map Pointing Solutions
Class 10 NCERT Civics Solutions
Class 10 NCERT Civics Notes
Class 10 NCERT Civics Extra Questions
Class 10 NCERT Geography Solutions
Class 10 NCERT Geography Notes
Class 10 NCERT Geography Extra Questions
Class 10 NCERT History Solutions
→ Class 10 NCERT History Notes
Class 10 NCERT History Extra Questions
Class 10 NCERT Maths Solutions
Class 10 NCERT Science Solutions
Class 10 NCERT Science Notes
Class 10 NCERT Science Extra Questions

• Computer languages
Python Basics

• Extra Activities
Extra Activities

• Extra Knowledge
Extra Information
General Knowledge
Historical Places in India
Latest technology
Physical Sciences
Facts

• Mathematics quick links
Mathematical Terms
Maths Tricks