6500+ Quantitative Aptitude Questions and Answers With Explanation

Q:

If the standard deviation of a population is 3, what would be the population variance?

A) 9	B) 6
C) 8	D) 15

Answer & Explanation Answer: A) 9

Explanation:

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Filed Under: Probability
Exam Prep: Bank Exams

9 17109

Q:

25 divided by $\frac{1}{5}$ .

A) 1125	B) 5
C) 25	D) 125

Answer & Explanation Answer: D) 125

Explanation:

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Filed Under: Problems on Numbers
Exam Prep: Bank Exams

0 17027

Q:

Two cards are drawn from a pack of well shuffled cards. Find the probability that one is a club and other in King

A) 1/52	B) 1/26
C) 1/13	D) 1/2

Answer & Explanation Answer: B) 1/26

Explanation:

Let X be the event that cards are in a club which is not king and other is the king of club.
Let Y be the event that one is any club card and other is a non-club king.
Hence, required probability:
=P(A)+P(B)

= $[\frac{12 C_{1} * 1 C_{1}}{52 C_{2}}] + [\frac{13 C_{1} * 3 C_{1}}{52 C_{2}}]$

= $[12 * \frac{2}{52 * 51}] + [13 * 3 * \frac{2}{52 * 51}]$ = $\frac{24 + 78}{52 * 51}$ = $\frac{1}{26}$

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Filed Under: Probability

27 17027

Q:

The ratio of Pens and Pencils in a shop is 3 : 2 respectively. The average number of Pens and Pencils is 180. What is the number of Pencils in the shop?

A) 444	B) 344
C) 244	D) 144

Answer & Explanation Answer: D) 144

Explanation:

Given ratio of pens and pencils = 3 :2

Number of Pens = 3x

Number of Pencils = 2x

Average number of pencils & Pens = $\frac{3 x + 2 x}{2} =$ 180

5x = 360

=> x = 72

Hence, the number of pencils = 2x = 72 x 2 = 144.

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Filed Under: Ratios and Proportions
Exam Prep: AIEEE , Bank Exams , CAT , GATE
Job Role: Analyst , Bank Clerk , Bank PO , IT Trainer

36 17007

Q:

The average weight of a group of boys is 30 kg. After a boy of weight 35 kg joins the group, the average weight of the group goes up by 1 kg. Find the number of boys in the group originally ?

A) 6	B) 8
C) 4	D) 5

Answer & Explanation Answer: C) 4

Explanation:

Let the number of boys in the group originally be x.
Total weight of the boys = 30x
After the boy weighing 35 kg joins the group, total weight of boys = 30x + 35
So 30x + 35 + 31(x + 1) = > x = 4.

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

7 16991

Q:

A train overtakes two girls who are walking in the opposite direction in which the train is going at the rate of 3 km/h and 6km/h and passes them completely in 36 seconds and 30 seconds respectively. The length of the train is:

A) 120m	B) 150m
C) 125m	D) None of these

Answer & Explanation Answer: B) 150m

Explanation:

Let the length of the train e x meter, and let the speed of train be y km/h, then

$x = (y + 3) \times \frac{5}{18} \times 36$ --------(1) and

$x = (y + 6) \times \frac{5}{18} \times 30$ ---------(2)

From eq (1) and (2), we get

y = 12 km/h

Therefore, $x = (y + 3) \times \frac{5}{18} \times 36$ => x= 150 m

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Filed Under: Time and Distance

35 16950

Q:

The true discount on a bill of Rs. 2160 is Rs. 360. What is the banker's discount?

A) Rs. 432	B) Rs. 422
C) Rs. 412	D) Rs. 442

Answer & Explanation Answer: A) Rs. 432

Explanation:

F = Rs. 2160

TD = Rs. 360

PW = F - TD = 2160 - 360 = Rs. 1800

True Discount is the Simple Interest on the present value for unexpired time

=>Simple Interest on Rs. 1800 for unexpired time = Rs. 360

Banker's Discount is the Simple Interest on the face value of the bill for unexpired time

= Simple Interest on Rs. 2160 for unexpired time

=(360/1800)* 2160

= (1/5) * 2160

=Rs. 432

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Filed Under: Banker's Discount

3 16946

Q:

The distance between two cities A and B is 330 Km. A train starts from A at 8 a.m. and travel towards B at 60 km/hr. Another train starts from B at 9 a.m and travels towards A at 75 Km/hr. At what time do they meet?

A) 10 a.m	B) 10.30 a.m
C) 11 a.m	D) 11.30 a.m

Answer & Explanation Answer: C) 11 a.m

Explanation:

Suppose they meet x hrs after 8 a.m

then,

[Distance moved by first in x hrs] + [Distance moved by second in (x-1) hrs] = 330.

Quantitative Aptitude - Arithmetic Ability Questions

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