RD Chapter 1- Real Numbers Ex-1.1 |
RD Chapter 1- Real Numbers Ex-1.2 |
RD Chapter 1- Real Numbers Ex-1.3 |
RD Chapter 1- Real Numbers Ex-1.4 |
RD Chapter 1- Real Numbers Ex-1.5 |
RD Chapter 1- Real Numbers Ex-1.6 |
RD Chapter 1- Real Numbers Ex-VSAQS |

The exponent of 2 in the prime factorisation of 144, is

(a) 4

(b) 5

(c) 6

(d) 3

**Answer
1** :
(a)

The LCM of two numbersls 1200. Which of the following cannot be their HCF ?

(a) 600

(b) 500

(c) 400

(d) 200

**Answer
2** :

(b) LCM of two number = 1200

Their HCF of these two numbers will be the factor of 1200

500 cannot be its HCF

If n = 2^{3} x 3^{4} x 4^{4} x 7, then the number of consecutive zeroes in n, where n is a natural number, is

(a) 2

(b) 3

(c) 4

(d) 7

**Answer
3** :

**(c)** Because it has four factors n = 2^{3} x3^{4} x 4^{4} x 7

It has 4 zeroes

The sum of the exponents of the prime factors in the prime factorisation of 196, is

(a) 1

(b) 2

(c) 4

(d) 6

**Answer
4** :
(c)

The number of decimal places after which the decimal expansion of the rational number 23/2^{2}×5 will terminate, is

(a) 1

(b) 2

(c) 3

(d) 4

**Answer
5** :
(b)

(a) an even number

(b) an odd number

(c) an odd prime number

(d) a prime number

**Answer
6** :
(a)

(a) pq

(b) p

(c) p

(d) p

**Answer
7** :

**(c)** a and b are two positive integers anda =pq^{2} and b = p^{3}q, where p and q are prime numbers,then LCM=p^{3}q^{2}

(a) pq

(b) p

(c) p

(d) p

**Answer
8** :

**(a)** a = pq^{2} and b =p^{3}qwhere a and b are positive integers and p, q are prime numbers, then HCF =pq

(a) pq

(b) pq

(c) p

(d) p

**Answer
9** :

**(b)** m and n are two positive integers andm = pq^{3} and n = pq^{2}, where p and q are primenumbers, then HCF = pq^{2}

If the LCM of a and 18 is 36 and the HCF of a and 18 is 2, then a =

(a) 2

(b) 3

(c) 4

(d) 1

**Answer
10** :

(c) LCM of a and 18 = 36

and HCF of a and 18 = 2

Product of LCM and HCF = product of numbers

36 x 2 = a x 18

a = 36×2/18 = 4

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