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Q:

405 sweets were distributed equally among children in such a way that the number of sweets received by each child is 20% of the total number of children. How many sweets did each child recieve ?

A) 9 B) 10
C) 11 D) 12
 
Answer & Explanation Answer: A) 9

Explanation:

Let the total number of children be x. 

Then, x * (20% of x) = 405  

=> x * 20x/100 = 405 

15x2 = 405 

 

=> x=45 

 

Number of sweets received by each child = 20% of 45 = 9.

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Filed Under: Percentage

Q:

The sum of the number of boys and girls in a school is 150. if the number of boys is x, then the number of girls becomes x% of the total number of students. The number of boys is : 

A) 60 B) 70
C) 80 D) 90
 
Answer & Explanation Answer: A) 60

Explanation:

We have : x + (x% of 150 )= 150 

=> x+(x/100)*150] = 150

=> 52x = 150  

=> x = (150*2)/5 = 60

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Q:

A student multiplied a number by 3/5 instead of 5/3, What is the percentage error in the calculation ?

A) 54 % B) 64 %
C) 74 % D) 84 %
 
Answer & Explanation Answer: B) 64 %

Explanation:

Let the number be x.

Then, ideally he should have multiplied by  x by 5/3. Hence Correct result was x * (5/3)= 5x/3. 

 

By mistake he multiplied x by 3/5 . Hence the result with error  = 3x/5 

Then, error = (5x/3 - 3x/5) = 16x/15 

Error %  = (error/True vaue) * 100 = [(16/15) * x/(5/3) * x] * 100 = 64 %

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Q:

In a History examination, the average for the entire class was 80 marks. If 10% of the students scored 35 marks and 20% scored 90 marks, what was the average marks of the remaining students of the class ?

A) 25 B) 50
C) 75 D) 100
 
Answer & Explanation Answer: C) 75

Explanation:

Let the number of students in the class be 100 and let this required average be x.

Then, (10 * 95) + (20 * 90) + (70 * x) = (100 * 80)

=> 70x = 8000 - (950 + 1800) = 5250

=> x = 75.

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Filed Under: Percentage

Q:

While purchasing one item costing Rs. 400, I had to pay the sales tax at 7% and on another costing Rs. 6400, the sales tax was 9%. What percent of the sales tax I had to pay, taking the two items together on an average ?

A) 8 + 15/17 B) 2 + 13/17
C) 3 + 2/17 D) 5 + 13/12
 
Answer & Explanation Answer: A) 8 + 15/17

Explanation:

Total sales tax paid = 7% of Rs, 400 + 9% of Rs. 6400

                            =Rs. (7/100)*400 + (9/100)*6400 = Rs. (28 + 576) = Rs. 604. 

 

Total cost of the items = Rs. (400 + 6400) = Rs. 6800.

 

Required percentage =(604/6800*100) % = 81517%.

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Filed Under: Percentage

Q:

The population of a town was 1,60,000 three years ago, If it increased by 3%, 2.5% and 5% respectively in the last three years, then the present population in 

A) 155679 B) 167890
C) 179890 D) 177366
 
Answer & Explanation Answer: D) 177366

Explanation:

Present population =  160000 *  (1 + 3/100)(1 + 5/200)(1 + 5/100)= 177366.

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Filed Under: Percentage

Q:

A student has to obtain 33% of the total marks to pass. He got 125 marks and failed by 40 marks. The maximum marks are :

A) 500 B) 600
C) 800 D) 1000
 
Answer & Explanation Answer: A) 500

Explanation:

Given that the student got 125 marks and still he failed by 40 marks

 

=> The minimum pass mark = 125 + 40 = 165

 

Given that minimum pass mark = 33% of the total mark

 

=> total mark =33/100 =165

 

=> total mark = 16500/33 = 500

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Filed Under: Percentage

Q:

In an examination, 34% of the students failed in Mathematics and 42% faiied in English. If 20% of the students failed in both the subjects, then the percentage of students who passed in both the subjects was :

A) 34 % B) 44 %
C) 54 % D) 64 %
 
Answer & Explanation Answer: B) 44 %

Explanation:

n (A) = 34, n (B) = 42, n (A  ∩ B) = 20.

 

So, n (A  U B) = n (A) + n(B) - n(A ∩B) = 34 + 42 - 20 = 56.

 

Percentage failed in either or both the subjects = 56.

 

Hence, percentage passed = (100 - 66)% = 44%.

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Filed Under: Percentage