6500+ Quantitative Aptitude Questions and Answers With Explanation

Q:

From a group of 7 men and 6 women, five persons are to be selected to form a committee so that at least 3 men are there on the committee. In how many ways can it be done?

A) 564	B) 735
C) 756	D) 657

Answer & Explanation Answer: C) 756

Explanation:

We may have (3 men and 2 women) or (4 men and 1 woman) or (5 men only).

Required number of ways= $(7 C_{3} * 6 C_{2}) + (7 C_{4} * 6 C_{1}) + 7 C_{5}$ = 756.

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Filed Under: Permutations and Combinations

11 18404

Q:

The ratio of the ages of Maala and Kala is 4 : 3. The total of their ages is 2.8 decades. The proportion of their ages after 0.8 decades will be [1 Decade = 10 years]

A) 4:3	B) 12:11
C) 7:4	D) 6:5

Answer & Explanation Answer: D) 6:5

Explanation:

Let, Maala’s age = 4A and Kala’s age = 3A
Then 4A + 3A = 28
A = 4
Maala’s age = 16 years
and Kala’s age = 12 years
Proportion of their ages after 8 is = (16 + 8) : (12 + 8)
= 24 : 20
= 6 : 5

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Filed Under: Problems on Ages

41 18403

Q:

The banker's discount on a certain sum due 2 years hence is11/10of the true discount.

The rate percent is:

A) 10%	B) 7%
C) 8%	D) 5%

Answer & Explanation Answer: D) 5%

Explanation:

Let T.D. be Re. 1.

Then, B.D. = Rs.11/10= Rs. 1.10.

Sum = Rs. (1.10*1)/(1.10-1) = Rs. (110/10)= Rs. 11.

S.I. on Rs. 11 for 2 years is Rs. 1.10

Rate = [(100 x 1.10)/(11 x 2 )]% = 5%.

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Filed Under: Banker's Discount

7 18391

Q:

The sum of the two numbers is 12 and their product is 35.What is the sum of the reciprocals of these numbers?

A) 12/35	B) 1/35
C) 35/8	D) 7/32

Answer & Explanation Answer: A) 12/35

Explanation:

Let a and b are the numbers.Then a+b is 12 and ab is 35.

a+b/ab = 12/35

1/b + 1/a = 12/35

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Filed Under: Numbers

21 18366

Q:

Two numbers are 35% and 42% are less than a third number .How much percent is the second number less than the first ?

A) 10.769 %	B) 11.23 %
C) 10.4 %	D) 9.87 %

Answer & Explanation Answer: A) 10.769 %

Explanation:

I II III

65 58 100

65 -------- 7
100 ------ ? => 10.769%

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

12 18360

Q:

A circular swimming pool is surrounded by a concrete wall 4ft wide. If the area of the concrete wall surrounding the pool is 11/25 that of the pool, then the radius of the pool is?

A) 10ft	B) 20ft
C) 30ft	D) 40ft

Answer & Explanation Answer: B) 20ft

Explanation:

let the radius of the pool be Rft

Radius of the pool including the wall = (R+4)ft

Area of the concrete wall = $π [{(R + 4)}^{2} - R^{2}]$ = $π [(R + 4 + R) (R + 4 - R)] = 8 π (R + 2)$ sq feet

=> 8 $π (R + 2) = \frac{11}{25} {πR}^{2} = > 11 R^{2} = 200 (R + 2)$

Radius of the pool R = 20ft

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Filed Under: Area
Exam Prep: Bank Exams
Job Role: Bank PO

19 18347

Q:

What is the smallest number by which 2880 must be divided in order to make it into a perfect square ?

A) 2	B) 3
C) 4	D) 5

Answer & Explanation Answer: D) 5

Explanation:

By trial and error method, we get
2880/3 = 960 is not a perfect square
2880/4 = 720 is not a perfect square
2880/5 = 576 which is perfect square of 24
Hence, 5 is the least number by which 2880 must be divided in order to make it into a perfect square.

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Filed Under: Numbers
Exam Prep: AIEEE , Bank Exams , CAT , GATE , GRE
Job Role: Analyst , Bank Clerk , Bank PO

14 18330

Q:

Two pipes A and B can fill a tank in 24 hours and $17 \frac{1}{7}$ hours respectively. Harihar opened the pipes A and B to fill an empty tank and some times later he closed the taps A and B , when the tank was supposed to be full. After that it was found that the tank was emptied in 2.5 hours because an outlet pipe "C" connected to the tank was open from the beginning. If Harihar closed the pipe C instead of closing pipes A and B the remaining tank would have been filled in :

A) 2 hours	B) 8 hours
C) 6 hours	D) 4 hours

Answer & Explanation Answer: B) 8 hours

Explanation:

Efficiency of Inlet pipe A = 4.16% $(\frac{100}{24})$

Efficiency of Inlet pipe B = 5.83% $(\frac{100}{17 \frac{1}{7}})$

Therefore, Efficiency of A and B together = 100 %

Now, if the efficiency of outlet pipe be x% then in 10 hours the capacity of tank which will be filled = 10 * (10 - x)

Now, since this amount of water is being emptied by 'C' at x% per hour, then

$\frac{10 x (10 - x)}{x} = 2.5 h r s$

=> x = 8

Therefore, in 10 hours 20% tank is filled only. Hence, the remaining 80% of the capacity will be filled by pipes A and B in 80/10 = 8 hours

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Filed Under: Time and Work
Exam Prep: AIEEE , Bank Exams , CAT
Job Role: Bank Clerk , Bank PO

38 18326

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