146. The simple interest on a sum for 5 years is one fourth of the sum. The rate of interest per annum is
     

1. 1. 5%
      

   
   
   

   2. 6%
      

   
   
   

   3. 4%
      

   
   
   

   4. 8%

   
   
   

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1. View Hint View Answer Discuss in Forum

   As per the given in question ,
   

   Simple Interest	=	1
   Principal		4

   
   

   ∴ Rate =	S.I × 100
   	Principal × Time

   
   

   =	1 × 100	= 5% per annum
   	4 × 5

   
   Second method to solve this question :
   

   Here, n =	1	, T = 5 years,
   	4

   
   

   R =	n × 100
   	T

   
   

   Correct Option: A

   As per the given in question ,
   

   Simple Interest	=	1
   Principal		4

   
   

   ∴ Rate =	S.I × 100
   	Principal × Time

   
   

   =	1 × 100	= 5% per annum
   	4 × 5

   
   Second method to solve this question :
   

   Here, n =	1	, T = 5 years,
   	4

   
   

   R =	n × 100
   	T

   
   

   R =	1	×	100
   	4		5

   
   R = 5%

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147. Simple interest on a certain sum for 6 years is 9/25 of the sum. The rate of interest is

1. 1. 6%

   
   
   

   2. 6	1	%
      	2

   
   
   

   3. 8%

   
   
   

   4. 8	1	%
      	2

   
   
   

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1. View Hint View Answer Discuss in Forum

   According to question ,
   

   Simple Interest	=	9
   Principal		25

   
   

   Rate =	S.I × 100
   	Principal × Time

   
   

   Rate =	9	×	100	= 6%´per annum
   	25		6

   
   Second method to solve this question :
   

   Here, T = 6 years , n =	9
   	25

   
   

   Here, n =	9	T = 6 years,
   	25

   
   

   R =	n × 100
   	T

   
   

   Correct Option: A

   According to question ,
   

   Simple Interest	=	9
   Principal		25

   
   

   Rate =	S.I × 100
   	Principal × Time

   
   

   Rate =	9	×	100	= 6%´per annum
   	25		6

   
   Second method to solve this question :
   

   Here, T = 6 years , n =	9
   	25

   
   

   Here, n =	9	T = 6 years,
   	25

   
   

   R =	n × 100
   	T

   
   

   R =	9	×	100
   	25		6

   
   R = 6%

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148. The simple interest on a sum after 4 years is 1/5 of the sum. The rate of interest per annum is
     

1. 1. 4%
      

   
   
   

   2. 5%
      

   
   
   

   3. 6%
      

   
   
   

   4. 8%

   
   
   

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1. View Hint View Answer Discuss in Forum

   Let Principal = ₹100
   

   S.I. = 100 ×	1	= ₹ 20
   	5

   
   

   Rate =	20 × 100	= 5%
   	100 × 4

   
   Second method to solve this question :
   

   Here, T = 4 years , n =	1
   	5

   
   

   Here, n =	1	T = 4 years,
   	5

   
   

   R =	n × 100
   	T

   
   

   Correct Option: B

   Let Principal = ₹100
   

   S.I. = 100 ×	1	= ₹ 20
   	5

   
   

   Rate =	20 × 100	= 5%
   	100 × 4

   
   Second method to solve this question :
   

   Here, T = 4 years , n =	1
   	5

   
   

   Here, n =	1	T = 4 years,
   	5

   
   

   R =	n × 100
   	T

   
   

   R =	1	×	100
   	5		4

   
   R = 5%

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149. If a sum of money doubles itself in 8 years, then the interest rate in percentage is
     

1. 1. 8	1	%
      	2

   
   
   

   2. 10%

   
   
   

   3. 10	1	%
      	2

   
   
   

   4. 12	1	%
      	2

   
   
   

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1. View Hint View Answer Discuss in Forum

   Let principal be Rs. p.
   From question ,
   ∴ Amount = Rs. 2p
   Simple Interest = Amount - Principal = Rs. (2p – p) = Rs. p
   

   ∴ Rate =	SI × 100
   	Principal × Time

   
   

   Rate =	p × 100
   	p × 8

   
   

   =	25
   	2

   
   

   Correct Option: D

   Let principal be Rs. p.
   From question ,
   ∴ Amount = Rs. 2p
   Simple Interest = Amount - Principal = Rs. (2p – p) = Rs. p
   

   ∴ Rate =	SI × 100
   	Principal × Time

   
   

   Rate =	p × 100
   	p × 8

   
   

   =	25
   	2

   
   

   Rate = 12	1	% per annum
   	2

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150. At what percent of simple interest will a sum of money double itself in 15 years?
     

1. 1. 6	1	%
      	3

   
   
   

   2. 6	2	%
      	3

   
   
   

   3. 6	1	%
      	2

   
   
   

   4. 6%

   
   
   

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1. View Hint View Answer Discuss in Forum

   Let principal be Rs. p.
   ∴ Amount = Rs. 2p
   ∴ Simple Interest = Amount - Principal = Rs. (2p – p) = Rs. p
   

   ∴ Rate =	SI × 100
   	Principal × Time

   
   

   Rate =	p × 100	=	20
   	p × 15		3

   
   

   Correct Option: B

   Let principal be Rs. p.
   ∴ Amount = Rs. 2p
   ∴ Simple Interest = Amount - Principal = Rs. (2p – p) = Rs. p
   

   ∴ Rate =	SI × 100
   	Principal × Time

   
   

   Rate =	p × 100	=	20
   	p × 15		3

   
   

   Rate = 6	2	% per annum
   	3

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