6500+ Quantitative Aptitude Questions and Answers With Explanation

Q:

The sum of first 45 natural numbers is:

Answer

The sum of n natural numbers $\frac{n(n+1)}{2}=\frac{45\times 46}{2}=1035$

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Subject: Numbers

58 12393

Q:

The area of a field in the shape of a trapezium measures 1440sq m. The perpendicular distance between its parallel sides is 24cm. If the ratio of the sides is 5:3, the length of the longer parallel side is:

A) 75	B) 85
C) 95	D) 105

Answer & Explanation Answer: A) 75

Explanation:

Area of field = $\frac{1}{2} * (5 x + 3 x) * 24$ = 96x sq.m

96x = 1440 => x = $\frac{1440}{96}$ = 15

Hence, the length of longer parallel side = 5x = 75m

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Filed Under: Area
Exam Prep: Bank Exams
Job Role: Bank PO

7 12376

Q:

Water flows into a tank which is 200 m long and 150 m wide, through a pipe of cross-section (0.3m x 0.2m) at 20 km/h. In what time will the water level be 12m ?

A) 200 hrs	B) 240 hrs
C) 300 hrs	D) 270 hrs

Answer & Explanation Answer: C) 300 hrs

Explanation:

Volume of water collected in the tank in 1 hour

⇒ (0.3 × 0.2 × 20km × 1000mts) = 1200 m cubic

If after t hours, the water is at height of 12m,

1200t=200×150×12

⇒ t = 300 Hours.

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Filed Under: Pipes and Cistern
Exam Prep: AIEEE , Bank Exams , CAT , GATE
Job Role: Bank Clerk , Bank PO

25 12367

Q:

Shahrukh starts from Barabanki to Fatehpur , 1 hour after Ajay starts. Shahrukh meets Kajol 1.5 hours after Shahrukh starts. If the speed of Shahrukh is at least 20km/h faster than the speed of Kajol.

What is the minimum speed of Shahrukh to overtake Ajay, before he meets Kajol?

A) 30	B) 40
C) 60	D) None of these

Answer & Explanation Answer: D) None of these

Explanation:

Let t be the time after Kajol starts, when she meets Ajay, then

t = 300/(x+y)

This should be less than 2.5 or (x+y)>120

Since y= 3x/2 => y > 72

This (y>72) is greater than 67.5 km/h and hence Shahrukh will always overtake Ajay before he meets Kajol.

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Filed Under: Time and Distance

21 12356

Q:

8 years ago there were 5 members in the Arthur's family and then the average age of the family was 36 years. Mean while Arthur got married and gave birth to a child. Still the average age of his family is same now. What is the age of his wife at the time of his child's birth was.If the difference between the age of her child and herself was 26 years.

A) 25 years	B) 26 years
C) 20 years	D) can't be determined

Answer & Explanation Answer: B) 26 years

Explanation:

Since we know that the difference b/w the age of any two persons remains always constant, while the ratio of their ages gets changed as the time changes.

so, if the age of his child be x (presently)

Then the age of wife be x + 26 (presently)

Thus the total age = x + ( x + 26) = 32 [ $∵$ 252-220 =32]

=> x = 3

Therefore, The age of her child is 3 years and her self is 29 years. Hence her age at the time of the birth of her child was 26 years.

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Filed Under: Average

12 12337

Q:

One pipe can fill a tank three times as fast as another pipe. If together the two pipes can fill the tank in 36 min, then the slower alone will be able to fill the tank in:

A) 81 min	B) 108 min
C) 144 min	D) 192 min

Answer & Explanation Answer: C) 144 min

Explanation:

Let the slower pipe alone fill the tank in x minutes.

Then,faster pipe will fill it in x/3 minutes.

$= > \frac{1}{x} + \frac{3}{x} = \frac{1}{36} = > \frac{4}{x} = \frac{1}{36} = > x = 144 m i n s$

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Filed Under: Pipes and Cistern

22 12324

Q:

In a dairy farm, 40 cows eat 40 bags of husk in 40 days. In how many days one cow will eat one bag of husk?

A) 1	B) 1/40
C) 40	D) 80

Answer & Explanation Answer: C) 40

Explanation:

Let the required number of days be x.

Less cows, More days (Indirect Proportion)

Less bags, Less days (Direct Proportion)

$c o w s 1 : 40 : 40 : x b a g s 40 : 1 : 40 : x$

1 x 40 x x = 40 x 1 x 40

=> x = 40.

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Filed Under: Chain Rule

10 12315

Q:

A train with 120 wagons crosses Arun who is going in the same direction, in 36 seconds. It travels for half an hour from the time it starts overtaking the Arun ( he is riding on the horse) before it starts overtaking the Sriram( who is also riding on his horse) coming from the opposite direction in 24 seconds. In how much time (in seconds) after the train has crossed the Sriram do the Arun meets to Sriram?

A) 3560 sec	B) 3600 sec
C) 3576 sec	D) can't be determined

Answer & Explanation Answer: C) 3576 sec

Explanation:

Let the length of the train be L metres and speeds of the train Arun and Sriram be R, A and S respectively, then

$\frac{L}{R - A} = 36$ ---------- (i)

and $\frac{L}{R + K} = 24$ ---------(ii)

From eq.(i) and (ii)

3(R - A ) = 2 (R + K)

$\Rightarrow$ R = 3A + 2K

In 30 minutes (i.e 1800 seconds), the train covers 1800R (distance) but the Arun also covers 1800 A (distance) in the same time. Therefore distance between Arun and Sriram, when the train has just crossed Sriram

= 1800 ( R - A) - 24 ( A + K)

Time required = $\frac{1800 (R - A) - 24 (A + K)}{(A + K)}$

= (3600 - 24) = 3576 s

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Filed Under: Time and Distance

34 12306

Quantitative Aptitude - Arithmetic Ability Questions

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