6500+ Quantitative Aptitude Questions and Answers With Explanation

Q:

Adam and Smith are working on a project. Adam takes 6 hrs to type 36 pages on a computer, while Smith takes 5 hrs to type 40 pages. How much time will they take, working together on two different computers to type a project of 120 pages?

A) 8 hrs 45 min	B) 8 hrs 42 min
C) 8 hrs	D) 8 hrs 34 min

Answer & Explanation Answer: D) 8 hrs 34 min

Explanation:

Number of pages typed by Adam in 1 hour = 36/6 = 6
Number of pages typed by Smith in 1 hour = 40/5 = 8
Number of pages typed by both in 1 hour = (6 + 8) = 14
Time taken by both to type 110 pages = (120 * 1/14) = $8 \frac{4}{7}$ = 8 hrs 34 min.

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Filed Under: Time and Work
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10 5971

Q:

A passenger train is moving at a speed of 120 km/hr. If the length of the train is 101 meters, how long will it take to cross a railway platform 154 meters long ?

A) 6.24 sec	B) 6.58 sec
C) 7.325 sec	D) 7.65 sec

Answer & Explanation Answer: D) 7.65 sec

Explanation:

Here total distance = 154 + 101 = 255 mts
Given speed = 120 kmph = 120x5/18 m/sec
Hence, Time = d/s = 255x18/120x5 = 7.65 sec

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Filed Under: Problems on Trains
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8 5962

Q:

Simple interest on a certain sum of money for 3 years at 8% per annum is half the compound interest on Rs. 4000 for 2 years at 10% per annum. The sum placed on simple interest is

A) Rs.1650	B) Rs.1550
C) Rs.1750	D) Rs.1850

Answer & Explanation Answer: C) Rs.1750

Explanation:

C.I. =Rs[4000x(1+10/100)²-4000]

Rs.(4000x11/10x11/10-4000) = Rs.940.

Sum

=Rs. [420 *100 /3 * 8]

= Rs.1750.

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Filed Under: Compound Interest
Exam Prep: Bank Exams
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3 5962

Q:

Prasanna invested certain amount in three different schemes X, Y and Z with the rate of interest 10% p.a, 12% p.a and 15% p.a respectively. If the total interest accrued in one year was Rs. 3200 and the amount invested in Scheme Z was 150% of the amount invested in Scheme X and 240% of the amount invested in Scheme Y, what was the amount invested in Scheme Y by Prasanna ?

A) Rs.6000	B) Rs.4500
C) Rs.7500	D) Rs.5000

Answer & Explanation Answer: D) Rs.5000

Explanation:

Let a, b and c be the amounts invested in schemes X, Y and Z respectively. Then,

As we know:

Simple interest (S.I.) = PTR/100

(a × 10 × 1/100) + (b × 12 × 1/100) + (c × 15 × 1/100) = 3200

= 10a + 12b + 15c = 320000 .........(1)

Now, c = 240% of b = 12b/5 .........(2)

And, c = 150% of a = 3a/2 => a = 2/3 c = (2 × 12)b/(3 × 5) = 8b/5 .......(3)

From (1), (2) and (3), we have

16b + 12b + 36b = 320000 => 64b = 320000 => b = 5000

∴ Sum invested in Scheme Y = Rs.5000.

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Filed Under: Percentage
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9 5960

Q:

5 sin(x)+ 12 cos(x) + r is always greater than or equal to zero. What is the smallest value satisfied by 'r' ?

A) -13	B) 11
C) 13	D) -11

Answer & Explanation Answer: C) 13

Explanation:

Given,

5sinx + 12cosx ≥ -r

$\Rightarrow 13 (\frac{5}{13} \sin x + \frac{12}{13} \cos x) \geq - r$ cosx) ≥ -r

$\frac{5}{13}$ = cosA => sinA = $\frac{12}{13}$

=> 13(sinx cosA + sinA cosx) ≥ -r

=> 13(sin(x + A)) ≥ -r

we know that , -1 ≤ sin (angle) ≤ 1

=> 13sin (x + A) ≥ -13 $\Rightarrow r_{m i n} = 13$

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Filed Under: Simplification
Exam Prep: CAT
Job Role: Bank PO

8 5960

Q:

A towel, when bleached, was found to have lost 20% of its length and 10% of its breadth. The percentage of decrease in area is:

A) 10%	B) 10.08%
C) 20%	D) 28%

Answer & Explanation Answer: D) 28%

Explanation:

Let original length = x and original breadth = y.

Decrease in area = xy -[(80/100x) * (90/100y)]

=[(xy-(18/25)xy)]

=(7/25)xy

Decrease % =[(7/25)xy * (1/xy) * 100] =28%

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Filed Under: Volume and Surface Area

2 5951

Q:

The capacity of a tank is 2400 $m^{3}$ . A pump can be used both for filling and emptying the tank. The emptying capacity of the pump is 10 $m^{3}$ /minute higher than its filling capacity. And also, the pump needs 8 minutes less to empty the tank than to fill it. Find the filling capacity of the pump.

A) 46 cub.m/min	B) 44 cub.m/min
C) 48 cub.m/min	D) 50 cub.m/min

Answer & Explanation Answer: D) 50 cub.m/min

Explanation:

Let filling capacity of the pump be 'F' $m^{3} / \min$

Then, the filling capacity of the pump will be (F + 10) $m^{3} / \min$

From the given data,

$\frac{2400}{F} - \frac{2400}{F + 10} = 8 \Rightarrow 2400 [\frac{F + 10 - F}{F (F + 10)}] = 8 \Rightarrow F^{2} + 10 F - 3000 = 0 \Rightarrow F = 50 m^{3} / \min$

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Filed Under: Pipes and Cistern
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15 5944

Q:

A room contains 3 brown, 5 black and 4 white chairs. Two chairs are picked and are put in the lawn. What is the probability that none of the chairs picked is white ?

A) 14/33	B) 14/55
C) 12/55	D) 13/33

Answer & Explanation Answer: A) 14/33

Explanation:

Total number of chairs = (3 + 5 + 4) = 12.

Let S be the sample space.

Then, n(s)= Number of ways of picking 2 chairs out of 12

$=^{12} 12_{2} = \frac{12 \times 11}{2 \times 1} = 66$

Let n(E) = number of events of selecting 2 chairs for selecting no white chairs.

$=^{8} C_{2} = \frac{8 \times 7}{2 \times 1} = 28$

Therefore required probability = 28/66 = 14/33.

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Filed Under: Probability
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15 5941

Quantitative Aptitude - Arithmetic Ability Questions

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