Algebra(6th Grade > Mathematics ) Questions and answers for exam Preparation

6th Grade > Mathematics

ALGEBRA MCQs

Total Questions : 96 | Page 6 of 10 pages

The variable in the expression $(9 x + 32) \div 9$ is ___.

Discuss Question

Answer: Option A. ->
:
Variable is the unknown quantity which can have different values at different instances and they are usually represented by alphabets. In above expression,

x

is the variable.

Question 52.

When $5$ is added to a number, we get $15$ . How do we represent this in the form of an equation in variable $x$ ?

$x = 15 + 5$
$x - 5 = 15$
$x + 15 = 5$
$x + 5 = 15$

Discuss Question

Answer: Option D. ->

x + 5 = 15

:
D

Let us take the number to be $x$ .
When $5$ is added to the number, we get $x + 5.$
Now, we know that when $5$ is added to that number, we get $15$ .
Hence, $x + 5 = 15$ .

Question 53.

Which of the following is a variable?

Number of days in a week
5
Temperature of a place in a day at different times
Number of months in a year

Discuss Question

Answer: Option C. -> Temperature of a place in a day at different times
:
C
The temperature of a place in a day at different times will be different. So it is a variable.
The number of days in a week and the number of months in a year always remain the same. So these are constants.
5 has a fixed value. So it is a constant.

Question 54.

If the sum of successor and predecessor of a number is 14, then the number should be _____.

Discuss Question

Answer: Option C. -> 7
:
C
Let the number be

x

.
Therefore, the successor of number is

x

+ 1 and the predecessor is

x

- 1.
Given that the sum of successor and predecessor is 14.

∴ x + 1 + x - 1 = 14 \Rightarrow 2 x = 14 \Rightarrow x = \frac{14}{2} \Rightarrow x = 7

So, the number should be 7.

Question 55.

If $\frac{2}{x + 10} = \frac{8}{x}$ , then the value of x is

$\frac{- 40}{3}$
3
-40
$\frac{40}{3}$

Discuss Question

Answer: Option A. ->

\frac{- 40}{3}

:
A

$\frac{2}{x + 10} = \frac{8}{x} \Rightarrow 2 x = 8 \times (x + 10) \Rightarrow x = 4 \times (x + 10) \Rightarrow x = 4 x + 40 \Rightarrow - 40 = 4 x - x \Rightarrow - 40 = 3 x \Rightarrow x = \frac{- 40}{3}$

Question 56.

Solve for $x : \frac{x - 2}{3} = \frac{2 x}{7}$

7
-14
14
-7

Discuss Question

Answer: Option C. -> 14
:
C

$\frac{x - 2}{3} = \frac{2 x}{7} \Rightarrow 7 \times (x - 2) = 3 \times 2 x \Rightarrow 7 x - 14 = 6 x \Rightarrow 7 x - 6 x = 14 \Rightarrow x = 14$

Question 57.

The equation 5t - 4 = 1 is satisfied when the value of t = 1.

True
False

Discuss Question

Answer: Option A. -> True
:
A

In order to check whether the above equation 5t-4 =1 is satisfied for t =1, we simply put 1 in place of t, So substituting t = 1 in the equation , we get
LHS = 5 $\times$ (1) - 4 =1 and RHS = 1.
Since, LHS=RHS, t =1 satisfies the equation 5t-4 =1.

Question 58.

The cost of two red balls and five blue balls is ₹160. Then the correct equation for this situation among the given options is _______.
$(r : price of one red ball)$
$(b : price of one blue ball)$

$2 r + 5 b = ₹ 160$
$3 r + 5 b = ₹ 160$
$r + 5 b = ₹ 80$
$2 r - 5 b = ₹ 160$

Discuss Question

Answer: Option A. ->

2 r + 5 b = ₹ 160

:
A

Let the cost of one Red ball be $r$ .

Let the cost of one Blue ball be $b$ .

So, the algebraic equation will be $2 r + 5 b = ₹ 160$

Question 59.

Which of the following is/are algebraic expression/s?

2 $\times$ 8 + 9
2 $x$ + 3
$\frac{21}{5}$ + 8
$\frac{5}{x}$ $\times$ 12

Discuss Question

Answer: Option B. -> 2

x

+ 3
:
B and D
An algebraic expression should have numbers or constants, variables or unknowns (usually represented by alphabets) and mathematical operation like multiplication, addition etc.
Hence from the given option

2 x + 3

and

\frac{5}{x} \times 12

are algebraic expressions.

Question 60.

$(2 x^{2} + 3 x y + 4 x y^{2} + 5 z) is an algebraic expression.$

True
False
$r + 5 b = ₹ 80$
$2 r - 5 b = ₹ 160$

Discuss Question

Answer: Option A. -> True
:
A
2x², 3xy, 4xy²and 5z are terms and they are combined using the operator "+”.
Therefore, it is an algebraic expression.