Percentage All Competence Aptitude

Percentage All Competence Aptitude
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Question 11

The strength of a school increases and decreases in every alternate year by 10%. It started with increase in 2000. Then the strength of the school in 2003 as compared to that in 2000 was ?

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Let's denote the initial strength of the school in 2000 as \( S \).

- In 2001, there is a 10% increase, so the strength becomes \( 1.1S \).
- In 2002, there is a 10% decrease, so the strength becomes \( 0.9 \times 1.1S = 0.99S \).
- In 2003, there is a 10% increase, so the strength becomes \( 1.1 \times 0.99S = 1.089S \).

Now, let's find the percentage change in the strength from 2000 to 2003:

\[ \text{Percentage Change} = \left( \dfrac{\text{Final Strength} - \text{Initial Strength}}{\text{Initial Strength}} \right) \times 100 \]

\[ \text{Percentage Change} = \left( \dfrac{1.089S - S}{S} \right) \times 100 \]

\[ \text{Percentage Change} = \left( \dfrac{0.089S}{S} \right) \times 100 \]

\[ \text{Percentage Change} = 8.9\% \]

Therefore, the strength of the school in 2003 as compared to 2000 increased by 8.9%. Hence, the correct option is "increased by 8.9%".

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Question 12

In an office 40% of the staff is female, 40% of the females and 60% of the males voted for me. The percentage of votes I got was ?

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Let's denote the total number of staff as \( S \), the number of females as \( F \), and the number of males as \( M \).

1. \( 40\% \) of the staff is female, so the number of females (\( F \)) is \( 0.4 \times S \).
   \[ F = 0.4S \]

2. \( 60\% \) of the staff is male, so the number of males (\( M \)) is \( 0.6 \times S \).
   \[ M = 0.6S \]

3. \( 40\% \) of the females voted for you, so the number of female votes is \( 0.4 \times F \).
   \[ \text{Female votes} = 0.4 \times 0.4S \]

4. \( 60\% \) of the males voted for you, so the number of male votes is \( 0.6 \times M \).
   \[ \text{Male votes} = 0.6 \times 0.6S \]

Now, let's find the total number of votes (\( \text{Total votes} \)):
   \[ \text{Total votes} = \text{Female votes} + \text{Male votes} \]    \[ \text{Total votes} = 0.4 \times 0.4S + 0.6 \times 0.6S \]

   Simplify the expression:
   \[ \text{Total votes} = 0.16S + 0.36S \]    \[ \text{Total votes} = 0.52S \]

Now, find the percentage of votes you got:
   \[ \text{Percentage of votes} = \left( \dfrac{\text{Total votes}}{\text{Total staff}} \right) \times 100 \]    \[ \text{Percentage of votes} = \left( \dfrac{0.52S}{S} \right) \times 100 \]    \[ \text{Percentage of votes} = 52\% \]

Therefore, the percentage of votes you got was \( 52\% \). Hence, the correct option is "52%".

Not clear enough?

Question 13

If a man receives on one-fourth of his capital 3% interest, on two third 5% and on the remainder 11%, the percentage he receives on the whole is ?

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Let's denote the capital as C. According to the given information:

1. One-fourth of the capital receives 3% interest, which is (1/4) * C * 3/100.
2. Two-thirds of the capital receives 5% interest, which is (2/3) * C * 5/100.
3. The remainder (1 - 1/4 - 2/3) receives 11% interest, which is (1/12) * C * 11/100.

Now, let's add these interest amounts to find the total interest:

\[ \text{Total Interest} = \dfrac{1}{4} \cdot C \cdot \dfrac{3}{100} + \dfrac{2}{3} \cdot C \cdot \dfrac{5}{100} + \dfrac{1}{12} \cdot C \cdot \dfrac{11}{100} \]

Combine the terms:

\[ \text{Total Interest} = \dfrac{3C}{400} + \dfrac{10C}{300} + \dfrac{11C}{1200} \]

Now, find a common denominator:

\[ \text{Total Interest} = \dfrac{9C + 40C + 11C}{1200} \]

\[ \text{Total Interest} = \dfrac{60C}{1200} \]

Simplify:

\[ \text{Total Interest} = \dfrac{1}{20}C \]

To find the percentage, divide the total interest by the capital and multiply by 100:

\[ \text{Percentage} = \dfrac{\dfrac{1}{20}C}{C} \times 100 \]

\[ \text{Percentage} = \dfrac{1}{20} \times 100 \]

\[ \text{Percentage} = 5 \]

So, the percentage he receives on the whole is 5%. Therefore, the correct answer is 5.

Not clear enough?

Question 14

Due to an increase of 50% in the price of eggs, 4 eggs less are available for 24. The present rate of eggs per dozen is ?

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Let's denote the original price of eggs as \(P\) per dozen. 

Due to a 50% increase, the new price (\(P_{\text{new}}\)) is given by:

\[ P_{\text{new}} = P + 0.5 \times P = 1.5P \]

Now, the number of eggs available for the original price is \(12\) (a dozen). Due to a 50% increase in price, 4 eggs less are available for the new price.

So, the number of eggs available for the new price is \(12 - 4 = 8\).

Now, we can set up the equation:

\[ P_{\text{new}} \times \left( \dfrac{8}{12} \right) = 24 \]

Substitute the expression for \(P_{\text{new}}\):

\[ 1.5P \times \left( \dfrac{8}{12} \right) = 24 \]

Solving for \(P\):

\[ 1.5P \times \dfrac{2}{3} = 24 \]

\[ P = \dfrac{24 \times 3}{1.5 \times 2} \]

\[ P = 36 \]

So, the original rate of eggs per dozen (\(P\)) is 36. Therefore, the correct answer is 36.

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Question 15

An individual pays 30% income tax. On this tax he has to pay a surcharge of 10%. Thus, the net tax rate, he has to pay, is ?

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Let's denote the income before tax as \( I \). The individual pays 30% income tax on this amount, so the tax paid (\( T \)) is given by:

\[ T = 0.30 \times I \]

Now, there is a surcharge of 10% on this tax, so the total tax paid (\( \text{Total Tax} \)) is:

\[ \text{Total Tax} = T + 0.10 \times T \]

\[ \text{Total Tax} = 1.10 \times T \]

Substitute the expression for \( T \):

\[ \text{Total Tax} = 1.10 \times (0.30 \times I) \]

\[ \text{Total Tax} = 0.33 \times I \]

Now, to find the net tax rate, we need to calculate the percentage of the total tax with respect to the original income:

\[ \text{Net Tax Rate} = \left( \dfrac{\text{Total Tax}}{I} \right) \times 100 \]

\[ \text{Net Tax Rate} = \left( \dfrac{0.33 \times I}{I} \right) \times 100 \]

\[ \text{Net Tax Rate} = 33\% \]

Therefore, the net tax rate the individual has to pay is 33%. The closest option is 33%, so the correct answer is:

\[ \text{Net Tax Rate} = 33\% \]

Not clear enough?

Question 16

A man bought some eggs of which 10% are rotten. He gives 80% of the remainder to his neighbours. Now he is left out with 36 eggs. How many eggs he bought ?

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Let's denote the number of eggs the man bought as \( E \).

1. Initially, 10% of the eggs are rotten, so the remaining good eggs are \( 90\% \) of the total:
   \[ \text{Good eggs after first step} = 0.9 \times E \]

2. The man gives 80% of the remaining eggs to his neighbors, so the eggs he has left are \( 20\% \) of the good eggs after the first step:
   \[ \text{Eggs left after second step} = 0.2 \times (0.9 \times E) \]

According to the given information, he is left with 36 eggs:
   \[ 0.2 \times (0.9 \times E) = 36 \]

Now, solve for \( E \):
   \[ E = \dfrac{36}{0.2 \times 0.9} \]

   \[ E = \dfrac{36}{0.18} \]

   \[ E = 200 \]

Therefore, the man initially bought 200 eggs. So, the correct answer is 200.

Not clear enough?

Question 17

A Set A consists of integers 27, 28, 30, 32, and 33. If integer k is included in the average of set A will increase by 30%. What is the value of integer K ?

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Let's denote the average of the original set A as \( \bar{A} \).

The average of a set is calculated by summing up all the values in the set and then dividing by the number of values.

\[ \bar{A} = \dfrac{27 + 28 + 30 + 32 + 33}{5} \]

Now, if we include integer \( k \) and the average increases by 30%, the new average (\( \bar{A'} \)) is given by:

\[ \bar{A'} = 1.3 \times \bar{A} \]

Now, we can set up the equation:

\[ \dfrac{27 + 28 + 30 + 32 + 33 + k}{6} = 1.3 \times \bar{A} \]

Plug in the expression for \( \bar{A} \):

\[ \dfrac{150 + k}{6} = 1.3 \times \left( \dfrac{150}{5} \right) \]

Solve for \( k \):

\[ \dfrac{150 + k}{6} = 1.3 \times 30 \]

\[ 150 + k = 6 \times 39 \]

\[ 150 + k = 234 \]

\[ k = 84 \]

Therefore, the value of integer \( k \) is 84. So, the correct answer is 84.

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Question 18

A man received 8,80,000 as his annual salary of the year 2007 which was 10% more than his annual salary in 2006. His annual salary in the year 2006 was ?

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Let the annual salary in the year 2006 be \(S\). According to the given information, the annual salary in 2007 is 10% more than that in 2006, so:

\[ \text{Salary in 2007} = S + 0.10 \times S \]

Given that the salary in 2007 is \(8,80,000\), we can set up the equation:

\[ 8,80,000 = S + 0.10 \times S \]

Combine like terms:

\[ 8,80,000 = 1.10 \times S \]

Now, solve for \(S\):

\[ S = \dfrac{8,80,000}{1.10} \]

\[ S = 8,00,000 \]

Therefore, the annual salary in the year 2006 was \(8,00,000\). So, the correct answer is \(8,00,000\).

Not clear enough?

Question 19

If each side of a cube is increased by 10% the volume of the cube will increase by ?

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Let \(S\) be the original side length of the cube, and \(V\) be the original volume of the cube.

The original volume \(V\) is given by \(V = S^3\).

If each side of the cube is increased by 10%, the new side length (\(S_{\text{new}}\)) will be \(1.10 \times S\). The new volume (\(V_{\text{new}}\)) is given by \((1.10 \times S)^3\).

Now, let's find the percentage increase in volume:

\[ \text{Percentage Increase} = \left( \dfrac{V_{\text{new}} - V}{V} \right) \times 100 \]

\[ \text{Percentage Increase} = \left( \dfrac{(1.10 \times S)^3 - S^3}{S^3} \right) \times 100 \]

\[ \text{Percentage Increase} = \left( \dfrac{1.331 \times S^3 - S^3}{S^3} \right) \times 100 \]

\[ \text{Percentage Increase} = \left( \dfrac{0.331 \times S^3}{S^3} \right) \times 100 \]

\[ \text{Percentage Increase} = 33.1\% \]

Therefore, if each side of a cube is increased by 10%, the volume of the cube will increase by 33.1%. So, the correct answer is 33.1%.

Not clear enough?

Question 20

In an examination A got 25% marks more than B, B got 10% less than C and C got 25% more than D. If D got 320 marks out of 500, the marks obtained by A were ?

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Let's denote the marks obtained by D as \(D\), by C as \(C\), by B as \(B\), and by A as \(A\).

Given information:
1. \(C\) got 25% more than \(D\), so \(C = D + 0.25D = 1.25D\).
2. \(B\) got 10% less than \(C\), so \(B = C - 0.10C = 0.90C\).
3. \(A\) got 25% more than \(B\), so \(A = B + 0.25B = 1.25B\).
4. \(D\) got 320 marks out of 500, so \(D = 320\).

Now, let's calculate \(C\):\[ C = 1.25D = 1.25 \times 320 \]

\[ C = 400 \]

Now, let's calculate \(B\):\[ B = 0.90C = 0.90 \times 400 \]

\[ B = 360 \]

Finally, let's calculate \(A\):\[ A = 1.25B = 1.25 \times 360 \]

\[ A = 450 \]

Therefore, the marks obtained by A were 450. So, the correct answer is 450.

Not clear enough?

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