Tag: maths

Questions Related to maths

If HCF of numbers $408$ and $1032$ can be expressed in the form of $1032x -408 \times 5$, then find the value of $x$.

  1. $0$

  2. $1$

  3. $2$

  4. $3$


Correct Option: C
Explanation:
$408=2\times2\times2\times3\times17$

$1032=2\times2\times2\times3\times43$

Hence, $HCF=2\times2\times2\times3=24$

Now, $1032x-408\times5=24\Rightarrow 1032x=2064\Rightarrow x=2$

Find the LCM and HCF of the following integers by the prime factorization mass

  1. 12, 15 and 21

  2. 17, 23, and 29

  3. 8, 9 and 25

  4. 72 and 108

  5. 72 and 108

  6. 306 and 657


Correct Option: A

The ratio of two numbers is 15:11. If their HCF be 13 then these numbers will be

  1. 15, 11

  2. 75, 55

  3. 105, 77

  4. 195, 143


Correct Option: A

Mark the correct alternative of the following.
The HCF of $100$ and $101$ is _________.

  1. $1$

  2. $7$

  3. $37$

  4. None of these


Correct Option: A
Explanation:

The given number $100$ and $101$ are consecutive numbers and respectively even and odd numbers.

So the HCF is $1$.

If HCF of $210$ and $55$ is of the form $(210) (5) + 55 y$, then the value of $y$ is :

  1. $-19$

  2. $-18$

  3. $5$

  4. $55$


Correct Option: A
Explanation:

  HCF of 210 and 55 is 5

Given HCF = $(210)(5)+55y$
$5 =(210)(5)+55y$
On solving this equation we get $y=-19$
 So correct answer will be option A

When the HCF of $468$ and $222$ is written in the form of  $ 468 x + 222y$ then the value of $ x$ and $y$ is 

  1. $x =-9 \ and \ y =19$

  2. $x =9 \ and \ y = -19$

  3. $x =9\  and \ y = 19$

  4. $x =-9 \ and \ y =- 19$


Correct Option: A
Explanation:

HCF of $468$ and $222$
$468 = \left(222 \times 2\right) + 24$
$222 = \left(24\times\ 9\right) + 6$
$24 = \left(6\times\ 4\right) + 0$
$\therefore HCF = 6$

$6 = 222 - \left(24\times\ 9\right)$
$ = 222 - \left[\left(468 -222 \times 2\right) \times\ 9\right]  $ [where $468 = 222 \times 2 + 24$]
$ = 222 - \left[468 \times 9 -222 \times 2 \times 9\right]$
$= 222 - \left(468 \times9\right) - \left(222\times 18\right)$
$ = 222 + \left(222 \times 18\right) - \left(468 \times9\right)$
$= 222\left[1 + 18\right]-  468 \times 9$
$= 222 \times19-  468 \times 9$
$  = 468 \times -9 + 222\times 19$
$\therefore x=-9$ and $y=19$.

If the H.C.F. of $A$ and $B$ is $24$ and that of $C$ and $D$ is $56,$ then the H.C.F. of $A, B, C$ and $D$ is

  1. $4$

  2. $12$

  3. $8$

  4. $3$


Correct Option: C
Explanation:

Given the H.C.F. of $A$ and $B$ is $24$ and that of $C$ and $D$ is $56.$
Then the H.C.F. of $A, B, C$ and $D$ is the HCF of $24$ and $56$ which is $8.$

The HCF of $136 ,170 \ and \ 255$ is 

  1. $13$

  2. $15$

  3. $17$

  4. $1$


Correct Option: C
Explanation:

136)170(1

  -    136
-------------------
          34)136(4
                136
----------------------------
                 0</div>

34)255(7
   -  238
-------------------
        17)34(2
             34
------------------------
              0

The H.C.F. of two expressions is x and their L.C.M is $ \displaystyle x^{3}-9x  $  IF one of the expression is $ \displaystyle x^{2}+3x  $  then,the other expression is 

  1. $ \displaystyle x^{2}-3x $

  2. $ \displaystyle x^{3}-3x $

  3. $ \displaystyle x^{2}+9x $

  4. $ \displaystyle x^{2}-9x $


Correct Option: A
Explanation:

Let two expressions $p(x)$ and $q(x)$ then

$p(x)\times q(x)=L.C.M.\ \times\ H.C.F.$

Since $p(x)=x^2+3x$
$(x^2+3x)\times q(x)=(x^3-9x) \times\ x$
$(x^2+3x)\times q(x)=(x^2-3x) \times\ (x^2+3x)$

$q(x)=(x^2-3x)$
Hence, this is the required solution.