6500+ Quantitative Aptitude Questions and Answers With Explanation

Q:

Two pipes A and B can separately fill a cistern in 10 and 15 minutes respectively. A person opens both the pipes together when the cistern should have been was full he finds the waste pipe open. He then closes the waste pipe and in another 3 minutes the cistern was full. In what time can the waste pipe empty the cistern when fill ?

A) 8.21 min	B) 8 min
C) 8.57 min	D) 8.49 min

Answer & Explanation Answer: C) 8.57 min

Explanation:

1/10 + 1/15 = 1/6 x 3 = 1/2

1 - 1/2 = 1/2

1/10 + 1/15 - 1/x = 1/2

x = 8.57 min

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Filed Under: Pipes and Cistern
Exam Prep: AIEEE , Bank Exams , CAT , GATE
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36 15865

Q:

Find the total numbers greater than 4000 that can be formed with digits 2, 3, 4, 5, 6 no digit being repeated in any number ?

A) 120	B) 256
C) 192	D) 244

Answer & Explanation Answer: C) 192

Explanation:

We are having with digits 2, 3, 4, 5 & 6 and numbers greater than 4000 are to be formed, no digit is repeated.

The number can be 4 digited but greater than 4000 or 5 digited.

Number of 4 digited numbers greater than 4000 are
4 or 5 or 6 can occupy thousand place => 3 x ${}^{4}P_{3}$ = 3 x 24 = 72.

5 digited numbers = ${}^{5}P_{5}$ = 5! = 120

So the total numbers greater than 4000 = 72 + 120 = 192

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

21 15846

Q:

A box contains 5 detective and 15 non-detective bulbs. Two bulbs are chosen at random. Find the probability that both the bulbs are non-defective.

A) 5/19	B) 3/20
C) 21/38	D) None of these

Answer & Explanation Answer: C) 21/38

Explanation:

n(S) = ${}^{20}C_{2}$ = 190

n(E) = ${}^{15}C_{2}$ = 105

Therefore, P(E) = 105/190 = 21/38

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Filed Under: Probability

12 15827

Q:

Sachin is younger than Rahul by 7 years. If the ratio of their ages is 7:9, find the age of Sachin

A) 24.5	B) 25.5
C) 26.5	D) 27.5

Answer & Explanation Answer: A) 24.5

Explanation:

If Rahul age is x, then Sachin age is x - 7,

so, (x-7)/x =7/9

$\Rightarrow$ 9x - 63 = 7x
$\Rightarrow$ 2x = 63
$\Rightarrow$ x = 31.5

So Sachin age is 31.5 - 7 = 24.5

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Filed Under: Problems on Ages

60 15793

Q:

The perimeter of a square is equal to twice the perimeter of a rectangle of length 8cm and breadth 7cm. What is the circumference of a semicircle whose diameter is equal to the side of the square ?

A) 55.12 cm	B) 22.54 cm
C) 42.51 cm	D) 38.57 cm

Answer & Explanation Answer: D) 38.57 cm

Explanation:

We know that perimeter of rectangle = 2(l+b) = 2(8+7)= 30cm
Given perimeter of square is twice the perimeter of rectangle = 2(30) = 60cm
Therefore, side of the square is = 1/4 x 60 = 15cm
Circumference of the required semicircle = $πr + 2 r$ = $\frac{22}{7} \times \frac{15}{2} + 2 \times \frac{15}{2}$ = 23.57 + 15 = 38.57cm.

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Filed Under: Area
Exam Prep: GRE , GATE , CAT , Bank Exams , AIEEE
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6 15790

Q:

The average age of 80 boys in a class is 15. The average age of group of 15 boys in the class is 16 and the average of another 25 boys in the class is 14. What is the average age of the remaining boys in the class ?

A) 12.24 yrs	B) 13.25 yrs
C) 16 yrs	D) 15.25 yrs

Answer & Explanation Answer: D) 15.25 yrs

Explanation:

Total ages of 80 boys = 15 x 80 = 1200 yrs.
Total age of 16 boys = 15 x 16 = 240 yrs
Total age of 25 boys = 14 x 25 = 350 yrs.
Average age of remaining boys = 1200 - (240+350) / 80 - (25+15) = 610/41 = 15.25 yrs.

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Filed Under: Problems on Ages
Exam Prep: AIEEE , Bank Exams , CAT , GATE , GRE
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11 15783

Q:

A man invested Rs. 4455 in Rs. 10 shares quoted at Rs. 8.25. If the rate of dividend be 12%, his annual income is:

A) 107.04	B) 648
C) 500	D) 648.60

Answer & Explanation Answer: B) 648

Explanation:

Number of shares = $\frac{4455}{8.25}$ = 540.

Face value = Rs. (540 x 10) = Rs. 5400.

Annual income = $R s . (\frac{12}{100} * 5400)$ = Rs. 648.

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Filed Under: Stocks and Shares

6 15779

Q:

A man in a train notices that he can count 41 telephone posts in one minute. If they are known to be 50 metres apart, then at what speed is the train travelling?

A) 60 km/hr	B) 100 km/hr
C) 110 km/hr	D) 120 km/hr

Answer & Explanation Answer: D) 120 km/hr

Explanation:

Number of gaps between 41 poles = 40
So total distance between 41 poles = 40*50
= 2000 meter = 2 km
In 1 minute train is moving 2 km/minute.
Speed in hour = 2*60 = 120 km/hour

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Filed Under: Time and Distance
Exam Prep: GRE

25 15778

Quantitative Aptitude - Arithmetic Ability Questions

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