226. The number of pairs of natural numbers, the difference of whose squares is 45 will be

1. 1. 2

   
   
   

   2. 3

   
   
   

   3. 6

   
   
   

   4. 5

   
   
   

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1. View Hint View Answer Discuss in Forum

   Let the numbers be x and y where x > y
   ∴  x² − y² = 45
   ⇒  (x + y)(x – y) = 45
   Now, 45 = 5 × 9
   = 15 × 3 = 45 × 1
   ∴  Number of pairs = 3

   Correct Option: B

   Let the numbers be x and y where x > y
   ∴  x² − y² = 45
   ⇒  (x + y)(x – y) = 45
   Now, 45 = 5 × 9
   = 15 × 3 = 45 × 1
   ∴  Number of pairs = 3

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227. The value of   √19.36 + √0.1936 + √0.001936 + √0.00001936   is :

1. 1. 4.8484

   
   
   

   2. 4.8694

   
   
   

   3. 4.8884

   
   
   

   4. 4.8234

   
   
   

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1. View Hint View Answer Discuss in Forum

   √19.36 + √0.1936 + √0.001936 + √0.00001936
   = 4.4 + 0.44 + 0.044 + 0.0044
   = 4.8884

   Correct Option: C

   √19.36 + √0.1936 + √0.001936 + √0.00001936
   = 4.4 + 0.44 + 0.044 + 0.0044
   = 4.8884

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228. The value of	√	0.064 × 0.256 × 15.625	is
     		0.25 × 0.625 × 4.096

1. 1. 2

   
   
   

   2. 2.4

   
   
   

   3. 0.24

   
   
   

   4. 4.2

   
   
   

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1. View Hint View Answer Discuss in Forum

   Expression

   =	√	0.064 × 0.256 × 15.625
   		0.025 × 0.625 × 4.096

   
   

   =	√	64 × 256 × 15625
   		25 × 625 × 4096

   
   

   =	8 × 16 × 25	= 2
   	5 × 25 × 64

   Correct Option: A

   Expression

   =	√	0.064 × 0.256 × 15.625
   		0.025 × 0.625 × 4.096

   
   

   =	√	64 × 256 × 15625
   		25 × 625 × 4096

   
   

   =	8 × 16 × 25	= 2
   	5 × 25 × 64

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229. If (1101)² = 1212201, find the value of √121.220l .

1. 1. 110.1

   
   
   

   2. 11.01

   
   
   

   3. 1.101

   
   
   

   4. 11.001

   
   
   

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1. View Hint View Answer Discuss in Forum

   (1101)² = 1212201
   ⇒  1101 = √1212201
   √121.2201
   

   ⇒	√	121.2201	=	1101	= 11.01
   		10000		100

   Correct Option: B

   (1101)² = 1212201
   ⇒  1101 = √1212201
   √121.2201
   

   ⇒	√	121.2201	=	1101	= 11.01
   		10000		100

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230. The square root of   21	51	is
     	169

1. 1. 5	8
      	13

   
   
   

   2. 4	8
      	13

   
   
   

   3. 4	3
      	13

   
   
   

   4. 5	5
      	13

   
   
   

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1. View Hint View Answer Discuss in Forum

   = 21	51	=	21 × 169 + 51	=	3600
   	169		169		169

   
   

   ∴	√	21	51	=	√	3600	=	60
   			169			169		13

   
   

   = 4	8
   	13

   Correct Option: B

   = 21	51	=	21 × 169 + 51	=	3600
   	169		169		169

   
   

   ∴	√	21	51	=	√	3600	=	60
   			169			169		13

   
   

   = 4	8
   	13

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