6500+ Quantitative Aptitude Questions and Answers With Explanation

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 17418

Q:

A car mechanic purchased four old cars for Rs. 1 lakh. He spent total 2 lakh in the maintenance and repairing of these four cars. what is the average sale price of the rest three cars to get 50% total profit if he has already sold one of the four cars at Rs. 1.2 lakh?

A) 1.5 lakh	B) 1.1 lakh
C) 1.2 lakh	D) 1.65 lakh

Answer & Explanation Answer: B) 1.1 lakh

Explanation:

Total cost of 4 cars = 1+2 = 3 lakh

Total S.P of 4 cars = 3 x 1.5 = 4.5 lakh ( $S i n c e S . P = \frac{(100 + G a i n %)}{100} x C . P$ )

S.P of 1 car = 1.2 lakh

S.P of rest 3 cars = 4.5 - 1.2 = 3.3 lakh

Average S.P of all the 3 cars = 1.1 lakh

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

64 17408

Q:

In a class of 39 students the ratio of boys and girls is 2 : 1. Radhika ranks 15th among all the students from top and 8th among girls from bottom. How many boys are there below Radhika ?

A) 9	B) 17
C) 11	D) 15

Answer & Explanation Answer: B) 17

Explanation:

Total student= 39, boys : girls = 2:1, hence no of boys= 2/3(39)= 26
num of girls= 1/3(39) = 13 , since radhika ranked 15 among 39 student from top
and ranked 8 among girls from bottom , this means 7 girls are below radhika, rest 13-9= 5 girls are above her, now from 14 toper 5 are girls hence 14-5=9 boys.
Hence num of boys below radhika are 26-9=17

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

36 17408

Q:

By investing Rs. 1620 in 8% stock, Michael earns Rs. 135. The stock is then quoted at:

A) 80	B) 96
C) 106	D) 108

Answer & Explanation Answer: B) 96

Explanation:

To earn Rs. 135, investment = Rs. 1620.

To earn Rs. 8, investment = $R s . \frac{1620}{135} \times 8$ = Rs. 96.

Market value of Rs. 100 stock = Rs. 96.

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Filed Under: Stocks and Shares

17 17393

Q:

From the 50 liters of milk, 5 liters of milk is taken out and after it 5 liters of water is added to the rest amount of milk. Again 5 liters of milk and water is drawn out and it was replaced by 5 liters of water. If this process is continued similarly for the third time, the amount of milk left after the third replacement:

A) 45L	B) 36.45L
C) 40.5L	D) 42.5L

Answer & Explanation Answer: B) 36.45L

Explanation:

General Formula:

Final or reduced concentration = initial concentration x ${(1 - \frac{a m o u n t b e i n g r e p l a c e d i n e a c h o p e r a t i o n}{t o t a l a m o u n t})}^{n}$

where n is the number of times the same operation is being repeated. The "amount being replaced" could be pure or mixture as per the case. similarly ,"total amount" could also be either pure or mixture. Here amount being replaced denotes the quantity which is to be withdrawn in each time.

Therefore, $50 \times {(1 - \frac{5}{50})}^{3}$

= 36.45 L

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Filed Under: Alligation or Mixture

20 17385

Q:

Two trains starting at the same time from two stations 200 km apart and going in opposite directions cross each other at a distance of 110 km from one of the stations. What is the ratio of their speeds?

A) 9 : 20	B) 11 : 9
C) 11 : 20	D) None of these

Answer & Explanation Answer: B) 11 : 9

Explanation:

In the same time, they cover 110 km and 90 km respectively.

Therefore, Ratio of their speeds = 110 : 90 = 11 : 9

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Filed Under: Time and Distance

18 17381

Q:

How many necklace of 12 beads each can be made from 18 beads of different colours?

A) 18!	B) 18! x 19!
C) 18!(6 x 24)	D) 18! x 30

Answer & Explanation Answer: C) 18!(6 x 24)

Explanation:

Here clock-wise and anti-clockwise arrangements are same.

Hence total number of circular–permutations: $\frac{18 P_{12}}{2 * 12}$ = $\frac{18!}{6 * 24}$

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Filed Under: Permutations and Combinations

35 17353

Q:

If (89)² is added to the square of a number, the answer so obtained is 16202. What is the (1/26) of that number?

A) 5.65	B) 2.7
C) 3.5	D) 6.66

Answer & Explanation Answer: C) 3.5

Explanation:

Let the number is = x

(89)² + x² = 16202

x² = 8281

x = 91

=> (1/26) of 91 = 3.5

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Filed Under: Square Roots and Cube Roots
Exam Prep: AIEEE , Bank Exams , CAT
Job Role: Analyst , Bank Clerk , Bank PO

18 17330

Quantitative Aptitude - Arithmetic Ability Questions

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