Percentage All Competence Aptitude
Question 31
18% of which number is equal to 12% of 75 ?
Let's denote the unknown number as \( x \).
We are given that 18% of \( x \) is equal to 12% of 75:
\[ 0.18x = 0.12 \times 75 \]
Now, solve for \( x \):
\[ 0.18x = 9 \]
\[ x = \dfrac{9}{0.18} \]
\[ x = 50 \]
Therefore, the unknown number is 50.
So, the correct answer is 50.
Not clear enough?
Question 32
If 50% of (P β Q) = 30% of (P + Q) and Q = x% of P, then the value of x is ?
Let's break down the given information and set up the equations:
1. \(50\% \text{ of } (P - Q) = 30\% \text{ of } (P + Q)\)
\[0.5(P - Q) = 0.3(P + Q)\]
2. \(Q = x\% \text{ of } P\)
\[Q = \dfrac{x}{100}P\]
Now, let's work with the first equation:
\[0.5(P - Q) = 0.3(P + Q)\]
Distribute the percentages:
\[0.5P - 0.5Q = 0.3P + 0.3Q\]
Combine like terms:
\[0.2P = 0.8Q\]
Now, let's use the second equation:
\[Q = \dfrac{x}{100}P\]
Substitute this into the equation we derived:
\[0.2P = 0.8 \left(\dfrac{x}{100}P\right)\]
Simplify:
\[0.2P = \dfrac{8x}{100}P\]
Multiply both sides by 100 to get rid of the fraction:
\[20P = 8xP\]
Divide both sides by \(8P\):
\[x = \dfrac{20}{8} = 2.5\]
So, the value of \(x\) is 2.5, which corresponds to 25%.
Therefore, the correct answer is 25.
Not clear enough?
Question 33
If 15% of (A + B) = 25% of (A β B), then what per cent of B is equal to A ?
Let's set up the equation using the given information:
\[ 15\% \text{ of } (A + B) = 25\% \text{ of } (A - B) \]
This can be written as:
\[ 0.15(A + B) = 0.25(A - B) \]
Now, let's solve for the relationship between A and B:
\[ 0.15A + 0.15B = 0.25A - 0.25B \]
Combine like terms:
\[ 0.15B + 0.25B = 0.25A - 0.15A \]
\[ 0.40B = 0.10A \]
Divide both sides by 0.10A to isolate B:
\[ B = \dfrac{0.10A}{0.40} \]
Simplify:
\[ B = \dfrac{1}{4}A \]
Now, let's find what percent of B is equal to A:
\[ \text{Percentage} = \dfrac{A}{B} \times 100 \]
Substitute the expression for B:
\[ \text{Percentage} = \dfrac{A}{\dfrac{1}{4}A} \times 100 \]
\[ \text{Percentage} = \dfrac{4}{1} \times 100 = 400\% \]
Therefore, what percent of B is equal to A is 400%.
So, the correct answer is 400%.
Not clear enough?
Question 34
What percent of 3.6 kg is 72 gms ?
To find what percent 72 grams is of 3.6 kg, you can use the formula:
\[ \text{Percentage} = \left( \dfrac{\text{Part}}{\text{Whole}} \right) \times 100 \]
In this case, the part is 72 grams and the whole is 3.6 kg (which is equivalent to 3600 grams).
\[ \text{Percentage} = \left( \dfrac{72}{3600} \right) \times 100 \]
Simplify the fraction:
\[ \text{Percentage} = \left( \dfrac{1}{50} \right) \times 100 \]
\[ \text{Percentage} = 2\% \]
Therefore, 72 grams is 2% of 3.6 kg.
So, the correct answer is 2%.
Not clear enough?
Question 35
What is to be added to 15% of 160 so that the sum may be equal to 25% of 240 ?
Let's set up the equation based on the given information:
Let \( x \) be the value to be added to 15% of 160.
The sum of \( x \) and 15% of 160 should be equal to 25% of 240:
\[ x + 0.15(160) = 0.25(240) \]
Now, solve for \( x \):
\[ x + 24 = 60 \]
Subtract 24 from both sides:
\[ x = 60 - 24 \]
\[ x = 36 \]
Therefore, to make the sum equal to 25% of 240, you need to add 36.
So, the correct answer is 36.
Not clear enough?
Question 36
A dozen pairs of socks quoted at 180 are available at discount of 20%. How many pairs of socks can be bought for 48 ?
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Let's calculate the discounted price for a dozen pairs of socks.
Original price for a dozen pairs of socks = 180
Discount rate = 20%
Discount amount = 20% of 180 = 0.20 * 180 = 36
Discounted price = Original price - Discount amount = 180 - 36 = 144
Now, let's find the cost per pair after the discount:
Cost per pair = Discounted price / Number of pairs = 144 / 12 = 12
So, each pair costs 12.
Now, let's see how many pairs can be bought for 48:
Number of pairs = Total amount / Cost per pair = 48 / 12 = 4
Therefore, 4 pairs of socks can be bought for 48.
So, the correct answer is 4 pairs.
Not clear enough?
Question 37
When 60 is subtracted from 60% of a number, the result is 60. The number is ?
Let's denote the unknown number as \( x \). According to the given information:
\[ 60\% \text{ of } x - 60 = 60 \]
Translate this into an equation and solve for \( x \):
\[ 0.6x - 60 = 60 \]
Add 60 to both sides:
\[ 0.6x = 120 \]
Divide both sides by 0.6:
\[ x = \dfrac{120}{0.6} \]
\[ x = 200 \]
So, the number is 200.
Therefore, the correct answer is 200.
Not clear enough?
Question 38
When 75 is added to 75% of a number, the answer is the number. Find 40% of that number ?
Let's denote the unknown number as \( x \). According to the given information:
\[ 75 + 75\% \text{ of } x = x \]
Translate this into an equation and solve for \( x \):
\[ 75 + 0.75x = x \]
Subtract 0.75x from both sides:
\[ 75 = 0.25x \]
Divide both sides by 0.25:
\[ x = \dfrac{75}{0.25} \]
\[ x = 300 \]
Now, find 40% of that number:
\[ 0.40 \times 300 = 120 \]
Therefore, 40% of the number is 120.
So, the correct answer is 120.
Not clear enough?
Question 39
If x% of y% of 80 is the same as 25% of 900, then the value of xy is ?
Let's break down the given information and set up the equation:
\[ x\% \text{ of } y\% \text{ of } 80 = 25\% \text{ of } 900 \]
Translate this into an equation:
\[ \left(\dfrac{x}{100} \times \dfrac{y}{100} \times 80\right) = \dfrac{25}{100} \times 900 \]
Simplify both sides:
\[ \dfrac{xy}{125} \times 80 = \dfrac{225}{4} \]
Multiply both sides by \( \dfrac{125}{80} \) to solve for \( xy \):
\[ xy = \dfrac{225}{4} \times \dfrac{125}{80} \times 80 \]
\[ xy = \dfrac{225}{4} \times 125 \]
\[ xy = \dfrac{28125}{4} \]
So, the value of \( xy \) is \( \dfrac{28125}{4} \).
The closest option is 28125.
Therefore, the correct answer is 28125.
Not clear enough?
Question 40
50% of a number when added to 50 is equal to the number. The number is ?
Let's denote the unknown number as \( x \). According to the given information:
\[ 50\% \text{ of } x + 50 = x \]
Translate this into an equation and solve for \( x \):
\[ 0.5x + 50 = x \]
Subtract \( 0.5x \) from both sides:
\[ 50 = 0.5x \]
Divide both sides by 0.5:
\[ x = \dfrac{50}{0.5} \]
\[ x = 100 \]
So, the number is 100.
Therefore, the correct answer is 100.
