6500+ Quantitative Aptitude Questions and Answers With Explanation

Q:

Two trains 140 m and 160 m long run at the speed of 60 km/hr and 40 km/hr respectively in opposite directions on parallel tracks. The time (in seconds) which they take to cross each other, is:

A) 9	B) 9.6
C) 10	D) 10.8

Answer & Explanation Answer: D) 10.8

Explanation:

Relative speed = (60 + 40) km/hr =[ 100 x ( 5 / 18 ) ]m/sec = ( 250 /9 ) m/sec.
Distance covered in crossing each other = (140 + 160) m = 300 m.
Required time = [ 300 x ( 9/250 ) ] sec = ( 54/ 5 )sec = 10.8 sec.

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Filed Under: Problems on Trains

25 25159

Q:

In the 75 litres of mixture of milk and water, the ratio of milk and water is 4:1. The quantity of water required to make the ratio of milk and water 3:1 is

A) 1 litre	B) 3 litres
C) 4 litres	D) 5 litres

Answer & Explanation Answer: D) 5 litres

Explanation:

Total quantity of mixture = 75 litre

Milk : Water = 4 : 1

3 : 1

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Filed Under: Alligation or Mixture

50 25124

Q:

A and B can do a work in 4 hours and 12 hours respectively. A starts the work at 6 AM and they work alternately for one hour each. When will the work be completed?

A) 4 days	B) 5 days
C) 6 days	D) 7 days

Answer & Explanation Answer: C) 6 days

Explanation:

Work donee by A and B in the first two hours, working alternatively = First hour A + Second hour B = (1/4) + (1/12) = 1/3.

Thus, the total time required to complete the work = 2 (3) = 6 days

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Filed Under: Time and Work

45 25123

Q:

A man walks 6 km at a speed of $1 \frac{1}{2}$ kmph, runs 8 km at a speed of 2 kmph and goes by bus another 32 km. Speed of the bus is 8 kmph. Find the average speed of the man in kmph.

$A) 4 \frac{3}{14}$

B) $4 \frac{2}{13}$

C) $2 \frac{4}{13}$

D) $3 \frac{4}{14}$

A) Option A	B) Option B
C) Option C	D) Option D

Answer & Explanation Answer: B) Option B

Explanation:

Man walked 6 km at 1.5 kmph, again he walked 8 km at speed of 2 kmph and 40 km at a speed of 8kmph
time taken indivisually:
=> 6/1.5 = 4 m
=> 8/2 = 4 m
=> 40/8 = 5 m

Average speed of man= total distance/ total time
=> 54/13 = $4 \frac{2}{13}$ kmph

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Filed Under: Time and Distance
Exam Prep: GRE , GATE , CAT , Bank Exams , AIEEE
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17 25112

Q:

A train speeds past a pole in 15 seconds and a platform 100 m long in 25 seconds. Its length is:

A) 50 m	B) 150 m
C) 200 m	D) data inadequate

Answer & Explanation Answer: B) 150 m

Explanation:

Let the length of the train be x metres and its speed be y m/sec.
Then, (x/y)= 15 $\Rightarrow$ y =(x/15)

(x+100)/25 = x/15

=> 15(x + 100) = 25x

=> 15x + 1500 = 25x

=> 1500 = 10x

=> x = 150 m.

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Filed Under: Problems on Trains

39 25108

Q:

The ages of Krish and Vaibhav are in the proportion of 3 : 5. After 9 years, the proportion of their ages will be 3 : 4. Then the current age of Vaibhav is:

A) 10	B) 13
C) 15	D) 18

Answer & Explanation Answer: C) 15

Explanation:

Krish’s age = 3A and Vaibhav’s age = 5A

(3A+9)/(5A+9) = 3/4

=> 4 (3A + 9) = 3 (5A + 9)

=> A = 3

Therefore, Vaibhav’s age = 15 years.

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Filed Under: Problems on Ages

45 24936

Q:

In a two-digit number, if it is known that its unit's digit exceeds its ten's digit by 2 and that the product of the given number and the sum of its digits is equal to 144, then the number is :

A) 12	B) 24
C) 36	D) 48

Answer & Explanation Answer: B) 24

Explanation:

Let the ten's digit be x.

Then, unit's digit = x + 2.

Number = 10x + (x + 2) = 11x + 2

Sum of digits = x + (x + 2) = 2x + 2.

(11x + 2) (2x + 2) = 144

=> 22x^2+26x-140=0

=> (x - 2)(11x + 35) = 0

=> x = 2

Hence, Required Number = 11x + 2 = 24

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Filed Under: Problems on Numbers

28 24925

Q:

The principal that amounts to Rs.4913 in 3 years at $4 \frac{1}{3}$ % per annum compound interest compounded annually is

A) Rs.3096	B) Rs.4076
C) Rs.4085	D) Rs.4096

Answer & Explanation Answer: D) Rs.4096

Explanation:

principal = $A = 4913, T = 3, R = 4 \frac{1}{3}$

$P = {\frac{A}{(\frac{1 + R}{100})}}^{T}$

= Rs.4096

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Filed Under: Compound Interest
Exam Prep: GRE

30 24909

Quantitative Aptitude - Arithmetic Ability Questions

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