546. The price of rice has increased by 60%. In order to restore the original price, the new price must be reduced by

1. 1. 33	1	%
      	3

   
   
   

   2. 37	1	%
      	2

   
   
   

   3. 40%

   
   
   

   4. 45%

   
   
   

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1. View Hint View Answer Discuss in Forum

   Required per cent
   

   =	x	× 100
   	100 + x

   
   where x = 60%
   

   =	60	× 100 =	75	= 37	1	%
   	160		2		2

   Correct Option: B

   Required per cent
   

   =	x	× 100
   	100 + x

   
   where x = 60%
   

   =	60	× 100 =	75	= 37	1	%
   	160		2		2

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547. If the price of sugar increases by 20%, one can buy 2 kg less for Rs. 50. What is the amount of sugar that could be bought before price hike?

1. 1. 10 kg.

   
   
   

   2. 12 kg.

   
   
   

   3. 14 kg.

   
   
   

   4. 16 kg.

   
   
   

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1. View Hint View Answer Discuss in Forum

   Let original price of sugar be Rs. x per kg.
   New price
   

   = Rs		120x		= Rs		6x		per kg
   		100				5

   
   According to the question.
   

   	50	-	50	= 2
   	x		6x
   			5

   
   

   ⇒	50	-	50 × 5	= 2
   	x		6x

   
   

   ⇒	50	-	125	= 2
   	x		3x

   
   

   =	150 - 125	= 2
   	3x

   
   ⇒ 6x = 25
   

   ⇒ x = Rs.	25	= kg.
   	6

   
   ∴ Required quantity of sugar
   

   =	50
   	x

   
   

   	50	=	50 × 6	= 12kg.
   	25		25
   	6

   Correct Option: B

   Let original price of sugar be Rs. x per kg.
   New price
   

   = Rs		120x		= Rs		6x		per kg
   		100				5

   
   According to the question.
   

   	50	-	50	= 2
   	x		6x
   			5

   
   

   ⇒	50	-	50 × 5	= 2
   	x		6x

   
   

   ⇒	50	-	125	= 2
   	x		3x

   
   

   =	150 - 125	= 2
   	3x

   
   ⇒ 6x = 25
   

   ⇒ x = Rs.	25	= kg.
   	6

   
   ∴ Required quantity of sugar
   

   =	50
   	x

   
   

   	50	=	50 × 6	= 12kg.
   	25		25
   	6

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548. The price of an article is decreased by 10%. To restore it to its former value, the new price must be increased by :

1. 1. 9	1	%
      	11

   
   
   

   2. 10%

   
   
   

   3. 11%

   
   
   

   4. 11	1	%
      	9

   
   
   

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1. View Hint View Answer Discuss in Forum

   Required per cent
   

   =	Decrease%	× 100
   	100 – Decrease%

   
   

   =	10	× 100 =	100	= 11	1	%
   	100 - 10		9		9

   Correct Option: D

   Required per cent
   

   =	Decrease%	× 100
   	100 – Decrease%

   
   

   =	10	× 100 =	100	= 11	1	%
   	100 - 10		9		9

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549. The salary of a person is reduced by 20%. To restore the previous salary, his present salary is to be increased by

1. 1. 20%

   
   
   

   2. 25%

   
   
   

   3. 17.5%

   
   
   

   4. 22.5%

   
   
   

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1. View Hint View Answer Discuss in Forum

   Required percentage increase
   

   =	x	× 100
   	100 – x

   
   

   =		20		× 100
   		100 - 20

   
   

   =	20	× 100 = 25%
   	80

   Correct Option: B

   Required percentage increase
   

   =	x	× 100
   	100 – x

   
   

   =		20		× 100
   		100 - 20

   
   

   =	20	× 100 = 25%
   	80

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550. From 1980-1990, the population of a country increased by 20%. From 1990-2000, the population of the country increased by 20%. From 2000-2010, the population of the country increased by 20%.
     Then the overall increased population (in percentage) of the country from 1980-2010 was

1. 1. 72.2 %

   
   
   

   2. 60 %

   
   
   

   3. 72.8 %

   
   
   

   4. 62.8 %

   
   
   

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1. View Hint View Answer Discuss in Forum

   Using Rule 7,
   Single equivalent increase for 20% and 20%
   

   =		20 + 20 +	20 × 20		% = 44%
   			100

   
   Single equivalent increase for 44% and 20%
   

   =		44 + 20 +	44 × 20		%
   			100

   
   = (64 + 8.8) % = 72.8%

   Correct Option: C

   Using Rule 7,
   Single equivalent increase for 20% and 20%
   

   =		20 + 20 +	20 × 20		% = 44%
   			100

   
   Single equivalent increase for 44% and 20%
   

   =		44 + 20 +	44 × 20		%
   			100

   
   = (64 + 8.8) % = 72.8%

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