Students can Download Chapter 4 Simple Equations Ex 4.4, Question and Answers, Notes Pdf, KSEEB Solutions for Class 7 Maths, Karnataka State Board Solutions help you to revise complete Syllabus and score more marks in your examinations.

## Karnataka State Syllabus Class 7 Maths Chapter 4 Simple Equations Ex 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.

Solution:

Let the unknown number be’x’

8 times a number be 8x

According to the question

8x + 4 = 60

8x = 60 – 4

8x = 56

∴ The unknown number x be 7

b) One-fifth of a number minus 4 gives 3.

Solution:

Let the unknown number be x

Then according to the question

∴ That unknown number be 35.

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

Solution:

Let the unknown number be x

According to the question

∴ That unknown number be 24.

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

Solution:

Let the unknown number be x According to the question

2x – 11 = 15

2x = 15 + 11

2x = 26

∴ That unknown number be 13.

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

Solution:

Let the unknown number be x

According to the question

50 – 3x = 8

– 3x = 8 – 50

Therefore that unknown number be 14.

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

Solution:

Let the unknown number be x

According to the question

∴ That unknown number be 21

g) Anwar thinks of a number. If he takes away 7 from \(\frac{5}{2}\) of the number, the result is 23.

Solution:

Let the unknown number be x

According to the question

That unknown number be 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?

Solution:

Let the lowest score be x

According to the question

2x + 7 = 87

2x = 87 – 7 = 80

x = 80/2 = 40 x = 40

∴ The lowest score be 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°).

Solution:

Let the base angles of an isosceles triangle be x°

According to the question

2x° + 40° = 180°

2x° = 180° – 40°

2x°= 140

The base angles are 70° and 70°

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?

Solution:

Let the score of Rahul be ‘x’ runs

According to the question

x + 2x = 198

3x = 198

∴ Rahul’s score = x = 66 runs

Sachins score = 2x = 2 × 66 = 132 runs

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?

Solution:

Let Parmits marble be x

According to the question

5x + 7 = 37

5x = 37 – 7 = 30

∴ Parmits marble be = x = 6

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

Solution:

Let the age of Laxmi be ‘x’ years

According to the question

3x + 4 = 49

3x = 49 – 4 = 45

3x = 45

x = 45/3 = 15

∴ Lakshmi’s age is x = 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?

Solution:

Let the number of fruit trees be ‘x’

According to the question

3x + 2 = 77

3x = 77 – 2 = 75

∴ No. of fruit trees = x = 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!

Solution:

Let the number be ‘x’

According to the question

7x + 50 = 300 – 40

7x + 50 = 260

7x = 260 – 50 = 210

∴ That number be x = 30