Simple Equations(7th Grade > Mathematics ) Questions and answers for exam Preparation

7th Grade > Mathematics

SIMPLE EQUATIONS MCQs

Total Questions : 118 | Page 10 of 12 pages

Question 91.

Is $4 x + 5 - y = 0$ a linear equation in one variable?

True
False
$\frac{- 2}{3}$
$\frac{2}{3}$

Discuss Question

Answer: Option B. -> False
:
B

$4 x + 5 - y = 0$ has two variables x and y.

Therefore, $4 x + 5 - y$ is an equation in two variables.

Question 92.

Raju reads $\frac{2}{3}$ rd of a book. He finds that still there are 100 pages to be read. The total number of pages in the book are?

Discuss Question

Answer: Option B. -> False
:

If Raju reads $\frac{2}{3}$ rd of a book. He will still have
$\frac{1}{3}$ rd of the book to complete.
Let the total number of pages of the book be y
Then $\frac{1}{3} y = 100$
Hence y = 3 $\times$ 100
= 300

Question 93.

$x = 3$ is the solution of the equation $x + 3 = 0$ .

True
False
$\frac{- 2}{3}$
$\frac{2}{3}$

Discuss Question

Answer: Option B. -> False
:
B

The value of unknown variable which satisfies the equation is called solution of the equation.
So, substituting $x = 3$ , we get $3 + 3$ i.e. $6$ which is not equal to zero. So, $3$ is not the solution of the equation.

Question 94.

The sum of a number and its half is five less than twice the number. Which of the following equations represents given statement mathematically?

$x + \frac{x}{2}$ $= (2 x - 5)$
$x + \frac{a}{2}$ $= (5 - 2 x)$
$x + \frac{a}{2} = (5 - 2 a)$
$a + \frac{x}{2}$ $= 2 x - 5$

Discuss Question

Answer: Option A. ->

x + \frac{x}{2}

= (2 x - 5)

:
A

Let the number be ' x'.

Half of the number is \frac{x}{2} .

Similarly, twice of the number = 2 x .

Sum of the number and its half = x + \frac{x}{2}

5 less than twice the number = 2 x - 5

Given: Sum of the number and its half is five less than twice of the number.

∴ The required equation is x + \frac{x}{2} = 2 x - 5

Question 95.

If $a = x$ then which number satisfies the equation: $x + \frac{a}{2} = (2 x - 5)$ ?

$10$
$5$
$2$
$7$

Discuss Question

Answer: Option A. ->

10

:
A

The equation in the above question is $x + \frac{a}{2} = (2 x - 5)$
We need to find the value of $x$ .
Substituting the value ' $x = a$ ' and solving.

$\Rightarrow x + \frac{x}{2} = (2 x - 5)$

$\Rightarrow \frac{3 x}{2} = (2 x - 5)$

$\Rightarrow 2 x - \frac{3 x}{2} = 5$

$\Rightarrow \frac{x}{2} = 5$

$\Rightarrow x = 5 \times 2$
$\Rightarrow x = 10$

Question 96.

After buying a toy from the shop, I am left with ₹15 from my 100 rupees of pocket money. Then, the cost of toy (in rupees) is:

$15$
$100$
$85$
$75$

Discuss Question

Answer: Option C. ->

85

:
C

Let the cost of the toy be x as it is the unknown.
x + 15 = 100
x = 100 - 15 = ₹85
So, the cost of the toy= ₹85

Question 97.

Pavani has a certain number of chocolates; she gave one-third of the chocolates to her brother Arjun, one-sixth to her friend Preeti. She was then left with 30 chocolates. What is the sum of the number of chocolates did she give to Arjun and Preeti?

___

Discuss Question

Answer: Option C. ->

85

:
Let the number of chocolates Pavani has be

x

\frac{x}{3}

are given to Arjun. So now she is left with

x - \frac{x}{3} = \frac{2 x}{3}

chocolates
She gave

\frac{x}{6}

to Preeti. So, she is left with

\frac{2 x}{3}

\frac{x}{6}

\frac{4 x}{6}

\frac{x}{6}

\frac{3 x}{6}

\frac{x}{2}

So,

\frac{x}{2} = 30

x = 30 \times 2 = 60

Initially, Pavani had

60

chocolates. She gave

\frac{1}{3}

rd i.e.

\frac{60}{3}

= 20

to Arjun.

\frac{1}{6}

th i.e.

10

chocolates to Preeti.

Sum = 10 + 20 = 30

Question 98.

Karan spends ₹ 5000 on food which is $\frac{5}{8}$ th of his income. Karan's income is ___ (in rupess).

Discuss Question

Answer: Option C. ->

85

Let Karan' s income be $x$
$\frac{5}{8}$ of x = ₹ 5000
$x = ₹ \frac{5000 \times 8}{5}$
x = ₹ (1000 x 8) = ₹ 8000

Question 99.

A shopkeeper has an unknown weight in his shop. To find out the weight, he first weighs $1 k g$ of rice, and then weighs $1 k g$ of rice and the unknown weight together. The combined weight of the rice and the unknown weight is $1.5 k g$ . Find the unknown weight (in grams).