Quantitative Aptitude - Arithmetic Ability Questions

Q:

If the arithmetic mean of seventy-five numbers is calculated, it is 35. if each number is increased by 5, then mean of new numbers is :

A) 30 B) 40
C) 50 D) 60
 
Answer & Explanation Answer: B) 40

Explanation:

Let the numbers are x1,x2,.......x75

 

By Hypothesis ,x1+x2+....x7575=35 ......(i)

Mean of new numbers = x1+5+x2+5+.......x75+575

 

x1+x2+......x75+5*7575

 

x1+x2+......x7575+37575=35+5=40 By (i) 

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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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Filed Under: Percentage

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Q:

A fort had provision of food for 150 men for 45 days. After 10 days, 25 men left the fort. The number of days for which the remaining food will last, is:

A) 29/5 B) 37/4
C) 42 D) 54
 
Answer & Explanation Answer: C) 42

Explanation:

After 10 days : 150 men had food for 35 days.

 

 

 

Suppose 125 men had food for x days.

 

 

 

Now, Less men, More days (Indirect Proportion)

 

 

 

 125 : 150 :: 35 : x    =>    125 x x = 150 x 35

 

 

 

 =>

 

 

 

=> x = 42.

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Q:

Rahul went to purchase a Nokia mobile handset, the shopkeeper told him to pay 20% tax if he asked the bill. Rahul manages to get the discount of 5% on the actual saleprice of the mobile and he paid the shopkeeper Rs. 3325 without tax. Besides he manages to avoid to pay 20% tax on the already  discounted price, what is the amount of discount that he has gotten?

A) 750 B) 375
C) 875 D) 525
 
Answer & Explanation Answer: C) 875

Explanation:

CP = 100, SP (with tax) =120

 

New   SP = 100 - 5 = 95

 

 Effective discount = 120 - 95 = 25 

 

So, at SP of 95 ----> discount = 25

 

and      at SP of 3325 -----> discount = 2595×3325 = 875

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Filed Under: Profit and Loss
Exam Prep: AIEEE , Bank Exams , CAT
Job Role: Bank Clerk , Bank PO

54 24183
Q:

A man wants to sell his scooter .There are two offers one at Rs12000 cash and other at a credit of Rs12880 to be paid after 8 months ,money being at 18% per annum which is better offer?

A) Rs.12880 B) Rs.12000
C) Both are equally good D) None of the above
 
Answer & Explanation Answer: B) Rs.12000

Explanation:

PW of Rs.12,880 due 8 months hence  

= Rs. [12880 x 100] / [100+(18 x 8/12)] =Rs.11500 

Clearly 12000 in cash is a better offer.

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Filed Under: True Discount

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Q:

Find the volume (in cub.cm) of a hemisphere of diameter 28 cm.

 

A) 4789.67   B) 3675  
C) 2732 D) 5749.33
 
Answer & Explanation Answer: D) 5749.33

Explanation:
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Filed Under: Volume and Surface Area
Exam Prep: Bank Exams

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Q:

Given below are the ages in yrs of a group of children. What is the medium age?

 

7, 9, 8, 6 , 5, 3, 9, 2



A) 6.5 B) 5
C) 6.125 D) 6
 
Answer & Explanation Answer: A) 6.5

Explanation:
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Exam Prep: Bank Exams

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Q:

Find the appropriate relation for quantity1 and quantity2 in the following question:

Quantity 1: In an examination, Ankita scored 35 marks less than Puneeta. Puneeta scored 65 more marks than Meenakshi. Rakhi scored 115 marks, which is 20 marks more than Meenakshi's. Simpy scored 108 marks less than the maximum marks of the test. What approximate percentage of marks did Simpy score in the examination, if she got 67 marks more than Ankita?

Quantity 2: The length of a rectangle is increased by 60%. By what percent would the width have to be decreased to maintain the same area?

A) Quantity1 < Quantity2 B) Quantity1 ≤ Quantity2
C) Quantity1 ≥ Quantity2 D) Quantity1 > Quantity2
 
Answer & Explanation Answer: D) Quantity1 > Quantity2

Explanation:

Quantity1-
Rakhi’s marks= 115
Meenakshi’s marks= 115 - 20 = 95
Puneeta’s marks= 95 + 65= 160
Ankita’s marks=160 - 35= 125
Simpy’s marks= 125+ 67= 192
Total maximum marks= 192 + 108= 300
Required percentage marks of Simpy
192300×100=64%
Quantity2-
Let length and breadth be 100.

After increase in length it become 160, then
reduction in breadth be ‘x’
Now, 160*x= 100*100
Hence, x = 10000160=62.5

100-62.5=37.5%

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