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

7th Grade > Mathematics

SIMPLE EQUATIONS MCQs

Total Questions : 118 | Page 4 of 12 pages

Question 31. Is 4x+7 an equation? [1 MARK]

Discuss Question

:
No, because every equation must be equated with some quantities by including "=”. So, the given problemis an expression.

Question 32. After 7 years Sarosh's father's age will be 3 times that of Sarosh's age which will be equal to 6 times of Sarosh's present age. What is the sum of their present ages? [4 MARKS]

Discuss Question

:
Framing of equation: 1 Mark
Steps: 2 Marks
Result: 1 Mark
Let Sarosh's present age be

x

After 7 years, Sarosh's age will be

x + 7

Father's age after 7 years is

3 (x + 7)

This is equal to 6 times Sarosh's present age

= 6 x

So,

6 x = 3 (x + 7) = 3 x + 21

\Rightarrow 6 x = 3 x + 21

\Rightarrow 6 x - 3 x = 21

\Rightarrow 3 x = 21

\Rightarrow x = \frac{21}{3} = 7

Sarosh's present age is 7 years.
Father's age after 7 years is

6 \times 7 = 42 y e a r s

His present age is

42 - 7 = 35 y e a r s

Sum of their present ages

= 35 + 7 = 42 y e a r s

Question 33. When you subtract 10 from thrice a number, the result is 17. Find the unknown number. [2 MARKS]

Discuss Question

:
Framing the equation: 1 Mark
Result: 1 Mark
Let the number be y
Then,

3 y - 10 = 17

\Rightarrow 3 y = 17 + 10

\Rightarrow 3 y = 27

\Rightarrow y = 9

Question 34. The value of

y

that satisfies the equation

3 (y + 2) = 12

Discuss Question

Answer: Option B. -> 2
:
B

3 (y + 2) = 12

Dividing both the sides of the equation by 3,

\frac{3 (y + 2)}{3} = \frac{12}{3} y + 2 = 4

Subtracting 2 from both the sides of the equation,

y + 2 - 2 = 4 - 2

∴ y = 2

Question 35. 7 years hence, Sarosh's father age will be thrice that of Sarosh's age. Presently father's age is 6 times of Sarosh's age. Sum of their present ages is equal to:

___

Discuss Question

:
Let Sarosh's present age be

x

.
After 7 years Sarosh's age will be

x + 7

and, his father's age will be

3 (x + 7)

.
This is equal to 6 times Sarosh's present age, i.e.

= 6 x

So,

6 x = 3 (x + 7) = 3 x + 21

6 x - 3 x = 21

3 x = 21

x = 7

Sarosh's present age is 7 years.
Father's age after 7 years is,

6 \times 7 = 42 y e a r s

His present age is,

42 - 7 = 35 y e a r s

Sum of their present ages = 35 + 7 = 42

Question 36. For the equation:

3 z + \frac{7}{2}

\frac{5}{2}

, '

z

' is equal to ____.

13
−13
−23
23

Discuss Question

Answer: Option B. -> −13
:
B

3 z + \frac{7}{2} = \frac{5}{2}

\frac{6 z + 7}{2} = \frac{5}{2}

(by taking the LCM)

\frac{6 z + 7}{2} \times 2 = \frac{5}{2} \times 2

6 z + 7 = 5

6 z + 7 - 7 = 5 - 7

6 z = - 2

\frac{6 z}{6} = \frac{- 2}{6}

∴ z = \frac{- 1}{3}

Question 37. Is

4 x + 5 - y = 0

a linear equation in one variable?

True
False
−23
23

Discuss Question

Answer: Option B. -> False
:
B

4 x + 5 - y = 0

has two variables x andy.
Therefore,

4 x + 5 - y

is an equation in two variables.

Question 38.

x = 3

is the solution of the equation

x + 3 = 0

True
False
−23
23

Discuss Question

Answer: Option B. -> False
:
B
The value of unknown variable which satisfies the equation is called solutionof the equation.
So, substituting

x = 3

, we get

3 + 3

i.e.

6

which is not equal to zero. So,

3

is not the solutionof the equation.

Question 39. Tony scored twice as many runs as Kohli. Together they scored

6

runs short of triple century. How many runs did each score?

196,98
96,192
19,38
250,125

Discuss Question

Answer: Option A. -> 196,98
:
A
Runs scored by Kohli be

x

. Then, runs scored by Tony will be

2 x

2 x + x = 300 - 6 = 294

3 x = 294

x = \frac{294}{3} = 98

So, Kohli scores 98 and Tony scores 196 runs.

Question 40.

x + 3 = 8

is called an algebraic ______.

variable
expression
equation
statement

Discuss Question

Answer: Option C. -> equation
:
C
An algebraic expression having an equality sign is called an equation. An equation is a constraint placed on a variable which is in an expression.