Percentage- Aptitude Questions and Answers

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Due to an increase in the price of eggs by 30%, now 3 less eggs are available for Rs.9.10. The present rate per egg is?

A)
91 paise

B)
70 paise

C)
48 paise

D)
84 paise


Correct Answer :

91 paise


Explanation :

Let the original price of a egg= X
New price, 30% increased in the price => (1+30/100)X =>13X/10
according to question
9.10( 1/X - 1/(13X/10) )=3
(9.10/3)(3/13)=X
X=9.1/13


So present price of a egg i.e. new price=>13X/10
=>(13/10)(9.1/13) =>.91

44% of the students in the class are females and the number of male students is 42. Find the total number of students in the class?

A)
70

B)
65

C)
75

D)
45


Correct Answer :

75


Explanation :

% of females student =44
So % of male students=(100-44)=>56

Let the total number of students=X
then 56% of X <=> 56X/100=42
X=4200/56

Therefore total students = X => 75

The price of petrol falls down by 20%. By how much percent must a man increase his consumption, so as to keep his expenditure constant?

A)
42%

B)
25%

C)
20%

D)
10%


Correct Answer :

25%


Explanation :

Let initial price of petrol =Rs. 100 per ltr
Initial monthly consumption =100 ltr
Total monthly expenditure =100×100=Rs. 10000

New price of petrol(falls down by 20%)=Rs. 80 per ltr
Let new monthly consumption=x ltr
New monthly expenditure =80*x

to keep monthly expenditure remain constant⇒ 10000=80*x
⇒x=125

i.e., increase in consumption=25%

The height of a tree is 800cm and it increases 10% yearly. Find the height of the tree after three years?

A)
1000 cm

B)
1060.4 cm

C)
1052.6 cm

D)
1064.8 cm


Correct Answer :

1064.8 cm


Explanation :

The height of a tree after n yeras , if it increases at the rate of R% per annum= P [1+(R/100)]n
Thus,
The height of the tree after three years= 800 [1+(10/100)]3
=> 800 [11/10]3
=> .8*11*11*11
=> 1064.8 cm

The price of an apple is increased from Rs.50 per kg to Rs.75 per kg. By what percent a person shall need to decrease his consumption in order to have the same expenditure?

A)
20%

B)
25%

C)
16(2/3)%

D)
33(1/3)%


Correct Answer :

33(1/3)%


Explanation :

Let original consumption = 100 kg and new consumption = x kg,
So, 100*50 = x*75
x=200/3
Reduction in consumption (100-200/3)= 100/3 = 33(1/3)%

In an examination a candidate who got 30% of the total marks failed by 8 marks. Another candidate who got 35% marks scored 12 marks more than the passing marks. Total marks are?

A)
500

B)
400

C)
800

D)
300


Correct Answer :

400


Explanation :

Let x be the maximum marks,

Then (30% of x)+8 = (35% of x)-12

3*x/10 + 8 = 7*x/20 - 12
3*x + 80 = (7*x - 240)/2

6*x + 160 = 7*x -240
Hence,Minimum marks x=400

The salary of a worker is first increased by 30% and afterwards reduced by 30%. What is the net change in his salary?

A)
91% increase

B)
30% decrease

C)
9% decrease

D)
None of these


Correct Answer :

9% decrease


Explanation :

Let a original number is = 100
New number, increased by 30% = 100 + (30% of 100) = 130
Now it is reduced by 30% = 130 - (30% of 130) = 91

that means , in net it is 100 - 91 = 9% decreasing


Or
If something increased by x% and reduced by x% then net effect will be loss of (x/10)2 %
= (30/10)2
= 9 %

A boy, after giving away 80% of his pocket money to one companion and 6% of the remainder to another, has 94 paise left with him. How much pocket money did the boy have in the beginning(in rupees)?

A)
2

B)
2.5

C)
5

D)
10


Correct Answer :

5


Explanation :

Let the boy had Rs.x
Money given to his companion = 80% of x = 4x/5
Remaining money = x - 4x/5 = x/5
Money given to another companion = (6/100)*(x/5) = 3x/250
Remaining money => x/5 - 3x/250 = 94/100 (in rupees)
so 47x/250 = 94/100
x = 94*250/100*47
x = 5 (in rupees)

If the price of petrol is increased by 25%, by what percent the consumption of petrol must be reduced so that expenditure remains unchanged?

A)
20%

B)
25%

C)
33%

D)
50%


Correct Answer :

20%


Explanation :

Let initial price of petrol =Rs. 100 per ltr
Initial monthly consumption =100 ltr
Total monthly expenditure =100×100=Rs. 10000

New price of petrol(increased by 25%)=Rs. 125 per ltr
Let new monthly consumption=x ltr
New monthly expenditure =125*x

to keep monthly expenditure remain constant⇒ 10000=125*x
⇒x=80

i.e., reducedtion in consumption=20%

If the price of sugar is decreased by 25%, by what percent the consumption of sugar must be increase so that expenditure remains unchanged?

A)
20%

B)
25%

C)
33(1/3)%

D)
50%


Correct Answer :

33(1/3)%


Explanation :

Let initial price of Sugar=Rs. 100 per kg
Initial monthly consumption =100 kg
Total monthly expenditure =100×100=Rs. 10000

New price of Sugar(falls down by 25%)=Rs. 75 per kg
Let new monthly consumption=x kg
New monthly expenditure =75*x

to keep monthly expenditure remain constant⇒ 10000=75*x
⇒x=133(1/3)

i.e., increase in consumption=33(1/3)%

The first class ticket price of a circus is 12. When the price is decreased then the number of visitors increased by 80% and the total income is increased by 20%. Now, what is the price of each ticket?

A)
8

B)
10

C)
6

D)
15


Correct Answer :

8


Explanation :

Let 100 was the visitors.
On the ticket price 12 the total collection = 12 *100 = 1200

After decreased in price , let it be X.
New visitors= 100 + 80% of 100 =>180
New income, total income after 20% increased = 1200 + 20% of 1200=>1440

Therefore, New collection = X * 180 = 1440
=> X = 1440/180

thus, Price of each ticket ,X = 8

If M% of x is y and N% of y is x, then ?

A)
M+N = 100

B)
MN = 10000

C)
M/N= 100

D)
N/M = 100


Correct Answer :

MN = 10000


Explanation :

Y is M percent of X --> (MX/100)=Y

X is N percent of Y --> (NY/100)=X

Thus, after subsitute Y's value
=>(N/100)*(M/100)*X=X
=>MN=10000

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