Quantitative Aptitude - Arithmetic Ability Questions

Q:

A man travelled a distance of 80 km in 7 hours partly on foot at the rate of 8 km per hour and partly on bicycle at 16 km /hr. Find the distance travelled on foot ?

Answer

Let the Journey on foot be x km


Journey on cycle = (80 – x) km


x8+80-x16= 7 


=> x = 32km


Therefore,  Distance covered on foot in 4 hrs = ( 4 x 8) = 32 km

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54 19016
Q:

The difference between a positive proper fraction and its reciprocal is 9 / 20. Then the fraction is :

A) 3/5 B) 3/10
C) 4/5 D) 5/4
 
Answer & Explanation Answer: C) 4/5

Explanation:

Let the required fraction be x. Then, (1 / x )- x = 9/20
1 - x^(2) / x = 9 / 20  =>  20 - 20 * x^(2) = 9 * x.
20 * x^(2) + 9 *x - 20 = 0.
=> (4 * x + 5) (5 * x - 4) = 0.
=> x = 4 / 5.

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Filed Under: Numbers

34 19006
Q:

Amar can do a piece of work in 10 days. He works at it for 4 days and then Arun finishes it in 9 days. In how many days can Amar and Arun together finish the work ?

A) 4 days B) 8 days
C) 3 days D) 6 days
 
Answer & Explanation Answer: D) 6 days

Explanation:

4/10 + 9/x = 1     => x = 15 

 

Then both can do in 

1/10 + 1/15 = 1/6     => 6 days

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Filed Under: Time and Work
Exam Prep: GRE , GATE , CAT , Bank Exams , AIEEE
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19 18999
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 18992
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) 18% B) 28%
C) 38% D) 48%
 
Answer & Explanation Answer: B) 28%

Explanation:

Let original length = x and original breadth = y.  

Decrease in area = xy - 80100x×90100y = (7/25)xy

 

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

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

3 18944
Q:

A train moves past a telegraph post and a bridge 264 m long in 8 seconds and 20 seconds respectively. What is the speed of the train ?

A) 69.5 km/hr B) 70 km/hr
C) 79 km/hr D) 79.2 km/hr
 
Answer & Explanation Answer: D) 79.2 km/hr

Explanation:

Let the length of the train be x metres and its speed by y m/sec.


Then, x/y = 8 => x = 8y


Now, (x+264)/20 = y
8y + 264 = 20y
y = 22.
Speed = 22 m/sec = (22*18/5) km/hr = 79.2 km/hr.

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Filed Under: Problems on Trains

61 18918
Q:

The number of ways in which 8 distinct toys can be distributed among 5 children?

A) 5P8 B) 5^8
C) 8P5 D) 8^5
 
Answer & Explanation Answer: B) 5^8

Explanation:

As the toys are distinct and not identical,

For each of the 8 toys, we have three choices as to which child will receive the toy. Therefore, there are 58 ways to distribute the toys.

 

Hence, it is 58 and not 85.

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

16 18907
Q:

What value should come in place of the question mark (?) in the following question?

1637 + 1832 = 452 + (?)2

A) 38 B) 42
C) 46 D) 54
 
Answer & Explanation Answer: A) 38

Explanation:

3469 = 2025+?x?
? x ?= 3469-2025
? x ?= 1444
? = 38

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0 18902