6500+ Quantitative Aptitude Questions and Answers With Explanation

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 28691

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 28679

Q:

The total surface area of a cube is 253.5 sq.cm. Find its side (in cm).

A) 7.5	B) 5.5
C) 6.5	D) 8.5

Answer & Explanation Answer: C) 6.5

Explanation:

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

0 28634

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 28630

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 28620

Q:

The year next to 2005 will have the same calendar as that of the year 2005?

A) 2016	B) 2022
C) 2011	D) None

Answer & Explanation Answer: C) 2011

Explanation:

NOTE :

Repetition of leap year ===> Add +28 to the Given Year.

Repetition of non leap year

Step 1 : Add +11 to the Given Year. If Result is a leap year, Go to step 2.

Step 2: Add +6 to the Given Year.

Solution :

Given Year is 2005, Which is a non leap year.

Step 1 : Add +11 to the given year (i.e 2005 + 11) = 2016, Which is a leap year.

Step 2 : Add +6 to the given year (i.e 2005 + 6) = 2011

Therfore, The calendar for the year 2005 will be same for the year 2011

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Filed Under: Calendar

96 28588

Q:

A dealer sold two of his cattle for Rs. 500 each. On one of them he lost 10% on the other, he gained 10%. His gain or loss percent in the entire transaction was:

A) 10% loss	B) 1% loss
C) 1% gain	D) Neither loss nor profit

Answer & Explanation Answer: B) 1% loss

Explanation:

Loss%= (common gain or loss % / 10)² = (10/10)² % = 1%.

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Filed Under: Profit and Loss

56 28562

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 28549

Quantitative Aptitude - Arithmetic Ability Questions

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