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:

42% of an alloy was silver. If in a quantity of alloy there was 147 g of silver, what was the quantity of the other elements in the alloy?

 

 

A) 261 g B) 203 g
C) 273 g D) 350 g
 
Answer & Explanation Answer: B) 203 g

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2 842
Q:

Samar was given some money to take care of his travel during an 8-day sales drive he had to undertake. However he had to increase his stay by another 6 days and as a result his average daily travel allowance went down by Rs. 120. What was the amount that was sanctioned to him in the beginning?

 

A) ₹ 560 B) ₹ 840
C) ₹ 1120 D) ₹ 2240
 
Answer & Explanation Answer: D) ₹ 2240

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Q:

If the selling price of an article is 8% more than the cost price and the discount offered is 10% on the marked price of the article, then what is the ratio of the cost price to the marked price?

 

A) 5 : 6   B) 8 : 9  
C) 3 : 4   D) 4 : 5  
 
Answer & Explanation Answer: A) 5 : 6  

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9 835
Q:

A small scale business has the following expenses: procurement (25%), employees' salary (25%) and 50% for maintenance.


If the business pays a total salary of Rs. 2,00,000 then what is its maintenance expense?

 

A) ₹ 3,00,000 B) ₹ 2,00,000
C) ₹ 2,50,000 D) ₹ 4,00,000
 
Answer & Explanation Answer: D) ₹ 4,00,000

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1 832
Q:

A runner is running at a speed of 40 kim/h. If he runs at a speed of 30 km/h, then what will the decrease in the percentage of his speed be?

 

A) 30% B) 25%
C) 20% D) 15%
 
Answer & Explanation Answer: B) 25%

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Q:

Raghav spends 80% of his income. If his income increases by 12% and his expenditure increases by 17.5%, then what is the percentage decrease in his savings?

 

A) 12% B) 10%
C) 8% D) 15%
 
Answer & Explanation Answer: B) 10%

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3 823
Q:

Rahul’s salary is 50% more than Rohit’s salary. If Rahul saves Rs 2250 which is 8% of his salary, then what is Rohit’s salary (in Rs)?

 

A) 22250   B) 24450  
C) 26350   D) 18750
 
Answer & Explanation Answer: D) 18750

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Q:

56% of 375 is:

A) 210 B) 196
C) 224 D) 168
 
Answer & Explanation Answer: A) 210

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