# Set up an equation in the following cases:

(i) Irfan says that he has 7 marbles more than five times the marbles Parmit has. Irfan has 37 marbles. (Take m to be the number of Parmit’s marbles.)

(ii) Laxmi’s father is 49 years old. He is 4 years older than three times Laxmi’s age. (Take Laxmi’s age to be y years.)

(iii) 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. (Take the lowest score to be l.)

(iv) In an isosceles triangle, the vertex angle is twice either base angle. (Let the base angle be b in degrees. Remember that the sum of angles of a triangle is 180 degrees)

**Solution:**

We use simple linear equations to solve the questions.

(i) Let Parmit has m number of marbles

Then, Irfan has (5m + 7) marbles

Total number of marbles Irfan has = 37

So, 5m + 7 = 37

(ii) Let the age of Laxmi be y years

Laxmi’s father is four years older than three times Laxmi’s age

Then Laxmi's father's age = 3y + 4 years

The age of Laxmi’s father is 49 years.

According to question, 3y + 4 = 49

(iii) Let the lowest marks obtained by the student be l

Then the highest marks obtained by the student be 2l + 7

And the highest score is 87

Therefore, According to question, 2l + 7 = 87

(iv) Let the base angle of a triangle be b.

Then the vertex angle of the isosceles triangle = 2b.

According to question, b + b + 2b = 180°.

or 4b = 180°

**Video Solution:**

## Set up an equation in the following cases: (i) Irfan says that he has 7 marbles more than five times the marbles Parmit has. Irfan has 37 marbles. (Take m to be the number of Parmit’s marbles.) (ii) Laxmi’s father is 49 years old. He is 4 years older than three times Laxmi’s age. (Take Laxmi’s age to be y years.) (iii) 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. (Take the lowest score to be l.) (iv) In an isosceles triangle, the vertex angle is twice either base angle. (Let the base angle be b in degrees. Remember that the sum of angles of a triangle is 180 degrees).

### NCERT Solutions for Class 7 Maths - Chapter 4 Exercise 4.1 Question 6

Equations formed in the following cases are: (i) 5m + 7 = 37, (ii) 3y + 4 = 49, (iii) 2l + 7 = 87, (iv) 4b = 180°