Tag: maths

Questions Related to maths

$\dfrac {7}{9}$ is a/an _______ number.

maths rational and irrational numbers existence of irrational numbers irrational numbers properties of irrational numbers

  1. rational

  2. composite

  3. irrational

  4. prime

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Correct Option: A
Explanation:

$\dfrac{7}{9}$ is of the form  $\dfrac {p}{q}$ form , hence it is rational no.


$\sqrt {23}$ is not a ...... number.

maths rational and irrational numbers existence of irrational numbers irrational numbers properties of irrational numbers

  1. irrational

  2. co-prime

  3. composite

  4. rational

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Correct Option: D
Explanation:

As per the theorem, the square root of any prime number is irrational. $\sqrt {23}$ is a prime number, so is not a rational number. It is irrational.
Therefore, $D$ is the correct answer.

$(3 + \sqrt {5})$ is .............. 

maths rational and irrational numbers existence of irrational numbers irrational numbers properties of irrational numbers

  1. whole number

  2. an integer

  3. rational

  4. irrational

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Correct Option: D
Explanation:

Sum or difference of a rational and irrational number is irrational. Therefore, $D$ is the correct answer.

$m$ is not a perfect square, then $\sqrt {m}$ is 

maths rational and irrational numbers existence of irrational numbers irrational numbers properties of irrational numbers

  1.  an irrational number

  2. a composite number

  3. a rational number

  4. None of these as $m$ is not on a number line

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Correct Option: A
Explanation:
$\sqrt {m}$ is irrational when it is not being a perfect square.
Example $\sqrt3$ which is an irrational number.

Therefore, $A$ is the correct answer.

$\pi = 3.14159265358979........$ is an

maths rational and irrational numbers existence of irrational numbers irrational numbers properties of irrational numbers

  1. rational number

  2. whole number

  3. irrational number

  4. all of the above

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Correct Option: C
Explanation:

$\pi = 3.14159265358979........$ is a non-terminating and non-repeating irrational number.

Hence, option $C$ is correct.

How many of the following four numbers are rational?
$\sqrt{3}+\sqrt{3}, \sqrt{3}-\sqrt{3}, \sqrt{3} \times \sqrt{3}, \sqrt{3} / \sqrt{3}$

maths rational and irrational numbers existence of irrational numbers irrational numbers properties of irrational numbers

  1. One

  2. Two

  3. Three

  4. Four

Show answer
Correct Option: C
Explanation:

$\sqrt { 3 } +\sqrt { 3 } =2\sqrt { 3 } \quad irrational\quad number\ \sqrt { 3 } -\sqrt { 3 } =0\quad rational\quad number\ \sqrt { 3 } \times \sqrt { 3 } =3\quad rational\quad number\ \frac { \sqrt { 3 }  }{ \sqrt { 3 }  } =1\quad rational\quad number$

Now it is clear that there are three rational number so correct answer will be option C

Which of the following are irrational numbers?

maths rational and irrational numbers existence of irrational numbers irrational numbers properties of irrational numbers

  1. $\log _{ 5 }{ 325 } $

  2. $\log _{ 10 }{ 5 } $

  3. $\log _{ 2 }{ 512 } $

  4. $\log _{ 2 }{ 3 } $

Show answer
Correct Option: A,B,D

Consider the following statements:
1. $\dfrac {1}{22}$ cannot be written as a terminating decimal.
2. $\dfrac {2}{15}$ can be written as a terminating decimal.
3. $\dfrac {1}{16}$ can be written as a terminating decimal.
Which of the statements given above is/are correct?

maths rational and irrational numbers existence of irrational numbers irrational numbers properties of irrational numbers

  1. $1$ only

  2. $2$ only

  3. $3$ only

  4. $2$ and $3$

Show answer
Correct Option: C
Explanation:

1/22 is an irrational number hence it is a non terminating number

2/15 is an irrational number hence it is a non terminating number
1/16 is an rational number hence it is a terminating number

State whether the following statements are true or false. Justify your answers.
Every real number need not be a rational number

maths rational and irrational numbers existence of irrational numbers irrational numbers properties of irrational numbers

  1. True

  2. False

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Correct Option: A
Explanation:

Real number are all numbers on number line 

And  a rational number is any number that can be expressed as the quotient or fraction p/q of two integers, a numerator p and a non-zero denominator q. Since q may be equal to 1, every integer is a rational number.
And other numbers are not rational number are called irrational number.
Then every real number need not be a rational is true
Eg:  $\sqrt{3},\sqrt{2},\pi $

State whether the following statement is true or false:
All real numbers are irrational

maths rational and irrational numbers existence of irrational numbers irrational numbers properties of irrational numbers

  1. True

  2. False

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Correct Option: B
Explanation:

False,

The set of real numbers is made by combining the set of rational numbers and the set of irrational numbers. The real numbers include natural numbers or counting numbers, whole numbers, integers, rational numbers (fractions and repeating or terminating decimals), and irrational numbers.
Real number includes number like $\dfrac{1}{2},\dfrac{2}{3},\dfrac{3}{7}....$ which are not irrational numbers.

So the statement, all real numbers are irrational is false.