6500+ Quantitative Aptitude Questions and Answers With Explanation

Q:

The inner circumference of a circular race track, 14 m wide, is 440 m. Find radius of the outer circle

A) 44	B) 22
C) 33	D) 84

Answer & Explanation Answer: D) 84

Explanation:

Let inner radius be r metres. Then, 2 $π$ r = 440 ; r = $440 \times \frac{7}{44}$ = 70 m.

Radius of outer circle = (70 + 14) m = 84 m.

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

35 28791

Q:

A sequence $a, ax, {ax}^{2}, . . . . . ., {ax}^{n}$ , has odd number of terms. Then the median is

A) axn2+1	B) axn2-1
C) axn-1	D) axn2

Answer & Explanation Answer: D) axn2

Explanation:

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Filed Under: Probability
Exam Prep: Bank Exams

9 28755

Q:

Three numbers are in the ratio 4 : 5 : 6 and their average is 25. The largest number is :

A) 30	B) 40
C) 50	D) 60

Answer & Explanation Answer: A) 30

Explanation:

Let the numbers be 4x, 5x and 6x, Then, (4x + 5x + 6x ) / 3 = 25

=> 5x = 25

=> x = 5.

Largest number 6x = 30.

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Filed Under: Problems on Numbers

39 28696

Q:

A train travelling at a speed of 75 mph enters a tunnel $3 \frac{1}{2}$ miles long. The train is $\frac{1}{4}$ mile long. How long does it take for the train to pass through the tunnel from the moment the front enters to the moment the rear emerges?

A) 2.5 min	B) 3 min
C) 3.2 min	D) 3.5 min

Answer & Explanation Answer: B) 3 min

Explanation:

Total distance covered = $(\frac{7}{2} + \frac{1}{4})$ miles = $\frac{15}{4}$ miles

Time taken = $(\frac{15}{4 * 75})$ hrs = $\frac{1}{20}$ hrs = $(\frac{1}{20} * 60) m i n$ = 3 min

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Filed Under: Problems on Trains

36 28660

Q:

If the mean of a, b, c is M and ab + bc + ca = 0, then the mean of $\frac{a^{2} + b^{2} + c^{2}}{3}$ is :

A) M	B) 3 M^2
C) 2 (M/3)	D) M^2

Answer & Explanation Answer: B) 3 M^2

Explanation:

We have : ( a + b + c) / 3 = M or (a + b + c) = 3M.

Now. ${(a + b + c)}^{2} = {(3 M)}^{2} = 9 M^{2}$ .

$< = > a^{2} + b^{2} + c^{2} + 2 (a b + b c + c a) = 9 M^{2}$

$a^{2} + b^{2} + c^{2} = 9 M^{2}, (a b + b c + c a = 0)$

Required mean = $(\frac{a^{2} + b^{2} + c^{2}}{3}) = \frac{9 M^{2}}{3} = 3 M^{2}$ .

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

35 28659

Q:

If the length of a certain rectangle is decreased by 4 cm and the width is increased by 3 cm, a square with the same area as the original rectangle would result. Find the perimeter of the original rectangle.

A) 20	B) 30
C) 40	D) 50

Answer & Explanation Answer: D) 50

Explanation:

Let x and y be the length and breadth of the rectangle respectively.
Then, x - 4 = y + 3 or x - y = 7 ----(i)
Area of the rectangle =xy; Area of the square = (x - 4) (y + 3)
(x - 4) (y + 3) =xy <=> 3x - 4y = 12 ----(ii)
Solving (i) and (ii), we get x = 16 and y = 9.
Perimeter of the rectangle = 2 (x + y) = [2 (16 + 9)] cm = 50 cm.

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

21 28591

Q:

There are four hotels in a town. If 3 men check into the hotels in a day then what is the probability that each checks into a different hotel?

A) 1/2	B) 3/4
C) 4/7	D) 3/8

Answer & Explanation Answer: D) 3/8

Explanation:

Total cases of checking in the hotels = 4 x 4 x 4 = 64 ways.

Cases when 3 men are checking in different hotels = 4×3×2 = 24 ways.

Required probability =24/64 = 3/8

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Filed Under: Probability

46 28563

Q:

A sum of Rs. 725 is lent in the beginning of a year at a certain rate of interest. After 8 months, a sum of Rs. 362.50 more is lent but at the rate twice the former. At the end of the year, Rs. 33.50 is earned as interest from both the loans. What was the original rate of interest?

A) 3.46%	B) 4.5%
C) 5%	D) 6%

Answer & Explanation Answer: A) 3.46%

Explanation:

Let the original rate be R%. Then, new rate = (2R)%.

Note: Here, original rate is for 1 year(s); the new rate is for only 4 months i.e.1/3 year(s).

$(\frac{725 * R * 1}{100}) + (\frac{362.50 * 2 R * 1}{100 * 3}) = 33.50$

=> (2175 + 725) R = 33.50 x 100 x 3

=> (2175 + 725) R = 10050

=> (2900)R = 10050

=> $R = \frac{10050}{2900} = 3.46$

Original rate = 3.46%

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Filed Under: Simple Interest
Exam Prep: GRE

37 28517

Quantitative Aptitude - Arithmetic Ability Questions

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