6500+ Quantitative Aptitude Questions and Answers With Explanation

Q:

The marked price of an article is increased by 25% and the selling price is increased by 16.66%, then the amount of profit doubles. If the original marked price be Rs. 400 which is greater than the corresponding cost price by 33.33% , what is the increased selling price?

A) 240	B) 360
C) 420	D) 600

Answer & Explanation Answer: C) 420

Explanation:

Initially CP profit SP MP

100 x (100+x) 133.33

After Change 100 2x (100+x)

Now, Since (100+x) - 100 = 2x

$\frac{7}{6}$ x= 20%

CP Profit SP MP

100 20 120 133.33

So, 300 60 360 400

Again 300 120 420

So the increased selling price = Rs. 420

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Filed Under: Profit and Loss

62 16563

Q:

217 x 217 + 183 x 183 = ?

A) 84521	B) 87487
C) 80578	D) 78458

Answer & Explanation Answer: C) 80578

Explanation:

${(217)}^{2} + {(183)}^{2}$

= ${(200 + 17)}^{2} + {(200 - 17)}^{2}$

It is in the form of ${(a + b)}^{2} + {(a - b)}^{2} = 2 (a^{2} + b^{2})$

= 2(40000 + 289) = 80578.

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Filed Under: Simplification
Exam Prep: GATE , CAT , Bank Exams , AIEEE
Job Role: Bank PO , Bank Clerk

22 16562

Q:

Two trains having equal lengths, take 10 seconds and 15 seconds respectively to cross a post. If the length of each train is 120 meters, in what time (in seconds) will they cross each other when traveling in opposite direction?

A) 10	B) 25
C) 12	D) 20

Answer & Explanation Answer: C) 12

Explanation:

Speed of train 1 = $(\frac{120}{10}) m / s e c$ = 12 m/sec

Speed of train 2 = $(\frac{120}{15}) m / s e c$ = 8 m/sec

if they travel in opposite direction, relative speed = 12 + 8 = 20 m/sec

distance covered = 120 + 120 = 240 m

time = distance/speed = 240/20 = 12 sec

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Filed Under: Problems on Trains

22 16556

Q:

How many cubes of 10cm edge can be put in a cubical box of 1m edge

A) 10	B) 100
C) 1000	D) 10000

Answer & Explanation Answer: C) 1000

Explanation:

Number of cubes= (100x100x100) / (10x10x10)= 1000

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Filed Under: Volume and Surface Area
Exam Prep: Bank Exams
Job Role: Bank PO

45 16555

Q:

The number of ways that 8 beads of different colours be strung as a necklace is

A) 2520	B) 2880
C) 4320	D) 5040

Answer & Explanation Answer: A) 2520

Explanation:

The number of ways of arranging n beads in a necklace is $\frac{(n - 1)!}{2} = \frac{(8 - 1)!}{2} = \frac{7!}{2}$ = 2520

(since n = 8)

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Filed Under: Permutations and Combinations
Exam Prep: AIEEE , Bank Exams , CAT
Job Role: Bank Clerk , Bank PO

27 16547

Q:

The average age of a group of persons going for picnic is 16 years. Twenty new persons with an average age of 15 years join the group on the spot due to which their average age becomes 15.5 years. The number of persons initially going for picnic is :

A) 15	B) 20
C) 23	D) 24

Answer & Explanation Answer: B) 20

Explanation:

Let the initial number of persons be x. Then,

16x + 20 * 15 = 15.5 (x + 20) <=> 0.5x = 10 <=> x = 20.

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Filed Under: Average

19 16527

Q:

The third proportional to $(x^{2} - y^{2})$ and $(x - y)$ is :

A) (x + y )	B) (x - y)
C) (x + y) / ( x - y)	D) (x -y) / ( x + y)

Answer & Explanation Answer: D) (x -y) / ( x + y)

Explanation:

Let the third proportional to $(x^{2} - y^{2})$ and $(x - y)$ be z. Then,

$(x^{2} - y^{2}) : (x - y) : : (x - y) : z$

$= > (x^{2} - y^{2}) * z = {(x - y)}^{2}$

=> z= $\frac{{(x - y)}^{2}}{(x^{2} - y^{2})} = \frac{(x - y)}{(x + y)}$

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Filed Under: Ratios and Proportions

65 16524

Q:

If $a_{n} = \frac{1}{n + 1} + 1$ then find the value of $a_{1} + a_{3} + a_{5}$ .

A) 17/12	B) 27/12
C) 37/12	D) 47/12

Quantitative Aptitude - Arithmetic Ability Questions

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