Tag: highest common factor (h.c.f.)

Questions Related to highest common factor (h.c.f.)

Multiple choice maths hcf-lcm common factors and hcf hcf highest common factor (h.c.f.)

Three number are in the ratio of $3 : 4 : 5$ and their L.C.M. is $2400$. Their H.C.F. is:

  1. $40$
  2. $80$
  3. $120$
  4. $200$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let the numbers be $3x$, $4x$ and $5x$.
Then, their L.C.M. $= 60x$.
So, $60x = 2400$ or $x = 40$.
$\therefore $ The numbers are $\left( 3\times 40 \right) $, $\left( 4\times 40 \right) $ and $\left( 5\times 40 \right) $.
Hence, required H.C.F. $= 40$.

Multiple choice maths hcf-lcm common factors and hcf hcf highest common factor (h.c.f.)

The H.C.F. of $\dfrac { 9 }{ 10 }$, $\dfrac { 12 }{ 25 }$, $\dfrac { 18 }{ 35 }$ and $\dfrac { 21 }{ 40 } $ is:

  1. $\dfrac { 3 }{ 5 } $
  2. $\dfrac { 252 }{ 5 } $
  3. $\dfrac { 3 }{ 1400 } $
  4. $\dfrac { 63 }{ 700 } $
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Required H.C.F. $=\dfrac { H.C.F.\quad of\quad 9,12,18,21 }{ L.C.M.\quad of\quad 10,25,35,40 } = \dfrac { 3 }{ 1400 } $

Multiple choice maths hcf-lcm common factors and hcf hcf highest common factor (h.c.f.)

What is the HCF of $3.0, 1.2$ and $0.06$?

  1. $0.6$
  2. $0.06$
  3. $6.0$
  4. $6.06$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The given terms are $\dfrac {3}{1}, \dfrac {6}{5}$ and $\dfrac {3}{50}$.
H.C.F. of these terms $= \dfrac {\text{H.C.F. of}\ 3, 6, 3}{\text{L.C.M. of}\ 1, 5, 50}$
$= \dfrac {3}{50} = 0.06$

Multiple choice maths hcf-lcm common factors and hcf hcf highest common factor (h.c.f.)

What is the HCF of the polynomials $x^{4} - 3x + 2, x^{3} - 3x^{2} + 3x - 1$ and $x^{4} - 1$?

  1. $x - 1$
  2. $x + 2$
  3. $x^{2} - 1$
  4. None of the above

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$x^{4} - 3x + 2 = x^{4} - x^{3} + x^{3} - x^{2} + x^{2} - x - 2x + 2$
$= x^{3} (x - 1) + x^{2} (x - 1) + x(x - 1) - 2(x - 1)$
$= (x - 1) [x^{3} + x^{2} + x - 2]$
$x^{3} - 3x^{2} + 3x - 1 = (x - 1)^{3}$
$x^{4} - 1 = (x - 1) (x + 1) (x^{2} + 1)$
$HCF = x - 1$

Multiple choice maths hcf-lcm common factors and hcf hcf highest common factor (h.c.f.)

Find $HCF$ by finding factors:
$16$ and $56$.

  1. $6$
  2. $18$
  3. $8$
  4. $9$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Factorization of the following.
$16 = 2 \times 2 \times 2 \times 2$
$56 = 2 \times 2 \times 2 \times 7$
Since, the common factor is $2,2,8$,this implies that
$H.C.F = 2 \times 2 \times 2$
           $=8$
Hence,the correct option $C$.
Multiple choice maths hcf-lcm common factors and hcf hcf highest common factor (h.c.f.)

Find HCF by using prime factor method:
$54, 81$ and $99$.

  1. $8$
  2. $9$
  3. $10$
  4. $11$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Factorization of the following.
$54 = 2 \times 3 \times 3 \times 3$
$81 = 3 \times 3 \times 3 \times 3$
$99 = 3 \times 3 \times 11$
Since, the common factor is $3 \times 3$,this implies that
$H.C.F = 3 \times 3$
Hence,the correct option $B$.