# Ex.4.1 Q6 Simple-Equations Solution - NCERT Maths Class 7

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## Question

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).

Video Solution
Simple Equations
Ex 4.1 | Question 6

## Text Solution

What is unknown?

Equations for the different statements.

What is Known?

Statements of the equations.

Reasoning:

Read the statement carefully and frame the equation.

Steps:

(i) Let permit has $$m$$ number of marbles

Number of marbles Irfan has $$=5m + 7$$

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  $$=3y + 4$$

Age of Laxmi’s father is $$49$$ years

According to question,

$$3y + 4= 49$$

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

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 $$b$$

Vertex angle of the triangle $$= 2b$$

According to question,

\begin{align}b + b + 2b = 180^\circ\\ 4b = 180^\circ\end{align}

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