6500+ Quantitative Aptitude Questions and Answers With Explanation

Q:

The average of the two-digit numbers, which remain the same when the dibits inter-change their positions, is :

A) 53	B) 54
C) 55	D) 56

Answer & Explanation Answer: C) 55

Explanation:

Average = (11 + 22 + 33 + 44 + 55 + 66 + 77 + 88 + 99) / 9

=( (11 + 99) + (22 + 88) + (33 + 77) + (44 + 66) + 55) / 9

= (4 * 110 + 55)/9 = 495 / 9 = 55.

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Filed Under: Average

10 11075

Q:

A wholesale dealer allows a discount of 20 % on the marked price to the retailer. The retailer sells at 5% below the marked price. If the customer pays Rs.19 for an article, what profit is made by the retailer on it ?

A) Rs. 4	B) Rs. 3
C) Rs. 5	D) Rs. 1

Answer & Explanation Answer: B) Rs. 3

Explanation:

Let wholesaler dealers marked price = 100%, Retailer's C.P = 80%
And the retailer sells at 5% less than the marked price => S.P = 95%
If S.P of 95% of the retailer costs Rs.19 to customer,so its C.P of 80% will cost 80 x 19/95 = 16
Profit made by the retailer = 19-16 = Rs.3

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Filed Under: Profit and Loss
Exam Prep: AIEEE , Bank Exams , CAT , GATE , GRE
Job Role: Bank Clerk , Bank PO

11 11061

Q:

Four dice are thrown simultaneously. Find the probability that two of them show the same face and remaining two show the different faces.

A) 4/9	B) 5/9
C) 11/18	D) 7/9

Answer & Explanation Answer: B) 5/9

Explanation:

Select a number which ocurs on two dice out of six numbers (1, 2, 3, 4, 5, 6). This can be done in ${}^{6}C_{1}$ , ways.

Now select two distinct number out of remaining 5 numbers which can be done in ${}^{5}C_{2}$ ways. Thus these 4 numbers can be arranged in 4!/2! ways.

So, the number of ways in which two dice show the same face and the remaining two show different faces is

${}^{6}C_{1} \times {}^{5}C_{2} \times \frac{4!}{2!} = 720$

=> n(E) = 720

$∴ P (E) = \frac{720}{6^{4}} = \frac{5}{9}$

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Filed Under: Probability

8 11047

Q:

If y/(x - z) = (y + x)/z = x/y then find z : y : x ?

A) 1:2:3	B) 3:2:4
C) 4:3:2	D) 2:3:4

Answer & Explanation Answer: B) 3:2:4

Explanation:

Given, y/(x - z) = (y + x)/z = x/y
$y z = x y + x^{2} - y z - x z . . . . (1)$
Also $\frac{x}{y} = \frac{y}{x - z}$ $\Rightarrow x^{2} - x z = y^{2} . . . . (2)$
Using (1) and (2), we get yz = xy - yz + $y^{2}$
2yz = xy + $y^{2}$
2z = x + y
Only option (B) satisfies the equation.

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

19 11043

Q:

A farmer divides his herd of k cows among his 4 sons, so that one son gets one half of the herd, the second gets one-fourth, the third gets one-fifth and the fourth gets 9 cows. Then k is equal to ?

A) 160	B) 120
C) 140	D) 180

Answer & Explanation Answer: D) 180

Explanation:

Given total number of cows = k
Now, 1st son share = k/2
2nd son share = k/4
3rd son share = k/5
4th son share = 9

(k) + (k/4) + (k/5) + 9 = k
=> k - (19k/20) = 9
=> (20k-19k)/20 = 9
=> k = 180.

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Filed Under: Percentage
Exam Prep: AIEEE , Bank Exams , CAT , GATE , GRE
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17 11029

Q:

A coin is tossed twice if the coin shows head it is tossed again but if it shows a tail then a die is tossed. If 8 possible outcomes are equally likely. Find the probability that the die shows a number greater than 4, if it is known that the first throw of the coin results in a tail

A) 1/3	B) 2/3
C) 2/5	D) 4/15

Answer & Explanation Answer: A) 1/3

Explanation:

Here Sample space S = { HH, HT, T1, T2, T3, T4, T5, T6 }

Let A be the event that the die shows a number greater than 4 and B be the event that the first throw of the coin results in a tail then,

A = { T5, T6 }

B = { T1, T2, T3, T4, T5, T6 }

Therefore, Required probability = $P (\frac{A}{B}) = \frac{P (A \cap B)}{P (B)} = \frac{\frac{2}{8}}{\frac{6}{8}} = \frac{1}{3}$

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Filed Under: Probability

15 11018

Q:

A can do a work in 24 days. B is 20% more efficient than A. If C can do the work in 10 more days than B, find the time taken by A and C together to complete the work.

A) 43/3 days	B) 40/3 days
C) 50/3 days	D) 41/2 days

Answer & Explanation Answer: B) 40/3 days

Explanation:

A takes 24 days to complete a work.
B is 20% more efficient than A,
hence B will take (24*100)/120 = 20 days.
C takes (20+10) = 30 days.
Time taken by A & C in completing the work = (24*30)/(24+30) = (24*30)/54 = 40/3 days.

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Filed Under: Time and Work
Exam Prep: Bank Exams

1 10999

Q:

An automobile financier claims to be lending money at simple interest, but he includesthe interest every six months for calculating the principal. If he is charging an interest of10%, the effective rate of interest becomes:

A) 10%	B) 10.25%
C) 10.5%	D) none of these

Answer & Explanation Answer: B) 10.25%

Explanation:

Let the sum be Rs. 100. Then,

S.I. for first 6 months = Rs.[ (100 x 10 x 1)/(100 x 2) ]= Rs.5

S.I. for last 6 months =Rs.[(102 x 10 x 1)/(100 x 2) ] = Rs.5.25

So, amount at the end of 1 year = Rs. (100 + 5 + 5.25) = Rs. 110.25

Effective rate = (110.25 - 100) = 10.25%

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Filed Under: Simple Interest
Exam Prep: GRE

14 10977

Quantitative Aptitude - Arithmetic Ability Questions

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