FACTS  AND  FORMULAE  FOR  PERCENTAGE  QUESTIONS

 

 

I.Concept of Percentage : By a certain percent , we mean that many hundredths. Thus x percent means x hundredths, written as x%.

To express x% as a fraction : We have , x% = x/100.

Thus, 20% = 20/100 = 1/5;     

48% = 48/100 = 12/25, etc.

To express a/b as a percent : We have, ab=ab×100% .

 

Thus, 14=14×100%=25%

   

 

II. If the price of a commodity increases by R%, then the reduction in consumption so as not to increase the expenditure is R100+R×100%

If the price of the commodity decreases by R%,then the increase in consumption so as to decrease the expenditure is R100-R×100%

 

 

III. Results on Population : Let the population of the town be P now and suppose it increases at the rate of R% per annum, then :

1. Population after n years = P1+R100n

 

2. Population n years ago =  P1+R100n

 

 

IV. Results on Depreciation : Let the present value of a machine be P. Suppose it depreciates at the rate R% per annum. Then,

1. Value of the machine after n years = P1-R100n

 

2. Value of the machine n years ago = P1-R100n

 

 

V. If A is R% more than B, then B is less than A by

R100+R×100%    

If A is R% less than B , then B is more than A by 

R100-R×100%  

Q:

In new government policy, the price of onion is raised by 35%. By what % should a person reduce onion consumption so that the expenditure on it does not increase?

A) 25% B) 29%
C) 26% D) 33%
 
Answer & Explanation Answer: C) 26%

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Q:

Read the data given and answer the following questions

 

In a class of 60 students:

 

42 like Maths,

32 like English,

12 like neither Maths nor English

 

Students who like only Maths forms what percentage of the total number of students in the class?

 

A) 26.67% B) 24.22%
C) 28.80% D) 32.82%
 
Answer & Explanation Answer: A) 26.67%

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Q:

Read the data given and answer the following questions

 

In a class of 60 students:

 

42 like Maths,

32 like English,

12 like neither Maths nor English

 

How many students like exactly one subject?

A) 16 B) 12
C) 6 D) 22
 
Answer & Explanation Answer: D) 22

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Q:

Tanya got an increment of 15% in her salary. If her enhanced salary is Rs.14,030. What was her original salary?

A) Rs.12200 B) Rs.12300
C) Rs.12400 D) Rs.12000
 
Answer & Explanation Answer: A) Rs.12200

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Q:

The price of a Television is Rs.14000 inclusive of VAT. If the rate of VAT is 12%, find the basic price of the Television.

A) Rs.13500 B) Rs.13000
C) Rs.12500 D) Rs.12000
 
Answer & Explanation Answer: C) Rs.12500

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