# LCM & HCF

The LCM of two numbers is 30 and their HCF is 5. One of the numbers is 10. The other is:

[A]20

[B]15

[C]5

[D]25

**15**

Because, First number Second number = LCM HCF

Let the Second Number be x.

∴ 10x = 30 5

Hence option [B] is the right answer.

The LCM of two numbers is 1820 and their HCF is 26. If one number is 130 then the other number is :

[A]1264

[B]1690

[C]364

[D]70

**364**

Given that :

LCM of two numbers = 1820

HCF of those numbers = 26

and one of the number is 130, hence another number is :

Hence option [C] is the right answer.

The HCF of two numbers is 16 and their LCM is 160. If one of the number is 32, then the other number is:

[A]96

[B]48

[C]112

[D]80

**80**

We know that, First number Second number = LCM HCF

Second Number

Hence option [D] is the right answer.

The HCF of two numbers is 15 and their LCM is 300. If one of the number is 60, the other is:

[A]75

[B]65

[C]50

[D]100

**75**

Because, First number Second number = LCM HCF

∴ Second Number =

Hence option [A] is the right answer.

The HCF of two numbers 12906 and 14818 is 487. Their LCM is :

[A]600129

[B]800172

[C]400086

[D]200043

**400086**

Because product of two numbers = HCF LCM

12906 14818 = LCM 478

=

Hence option [C] is the right answer.

The LCM of two numbers is 864 and their HCF is 144. If one of the number is 288, the other number is :

[A]144

[B]432

[C]1296

[D]576

**432**

Required number =

So the second number is 432.

Hence option [B] is the right answer.

The HCF and LCM of two numbers are 12 and 336 respectively. If one of the number is 84, the other is :

[A]48

[B]36

[C]96

[D]76

**48**

First Number Second Number = HCF LCM

=> 84 second number = 12 336

Since second number =

Hence option [A] is the right answer.

The product of two numbers is 216. If the HCF is 6, then their LCM is :

[A]46

[B]48

[C]36

[D]76

**36**

Let the numbers be 6x and 6y where x and y are prime to each other.

Hence option [C] is the right answer.

The HCF and LCM of two numbers is 18 and 378 respectively. If one of the number is 54, then the other number is

[A]144

[B]196

[C]126

[D]236

**126**

Second Number

Hence option [C] is the right answer.

The HCF and product of two numbers are 15 and 6300 respectively. The number of possible pairs of the number is :

[A]3

[B]1

[C]4

[D]2

**2**

Let the number be 15x and 15y, where x and y are co-prime.

Since 15x 15y = 6300

So, two pairs are (7, 4) and (14, 2)

Hence the right option is [D].