Quantitative Aptitude - Arithmetic Ability Questions

Q:

A mother can do a certain job in x hours. Her daughter takes twice as long to do the job. Working together, they can do the job in 6 hours. How many hours does the mother take to do the job ?

A) 3 B) 6
C) 9 D) 12
 
Answer & Explanation Answer: C) 9

Explanation:

The mother completes the job in x hours.
So, the daughter will take 2x hours to complete the same job.

 

In an hour, the mother will complete 1/x of the total job.
In an hour, the daughter will complete 1/2x of the total job.

 

So, if the mother and daughter work together, in an hour they will complete 1/x + 1/2x of the job.
i.e., in an hour they will complete 3/2x of the job.

 

The question states that they complete the entire task in 6 hours if they work together.
i.e., they complete 1/6 th of the task in an hour.

 

Equating the two information, we get 3/2x = 1/6
By solving for x, we get 2x = 18 or x = 9.

 

The mother takes 9 hours to complete the job.

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Filed Under: Time and Work
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8 5362
Q:

Value of vehicle at end of each year depreciates at the rate of 3/5th of value at the beginning. If Initial value is 10,000Rs then at the end of three years its value is ? 

A) Rs. 6000 B) Rs. 3600
C) Rs. 2160 D) Rs. 415
 
Answer & Explanation Answer: C) Rs. 2160

Explanation:

End of first year     :  10000 x (3/5) = Rs. 6000
End of second year :  6000 x (3/5) = Rs. 3600
End of third year    :  3600 x (3/5) = Rs. 2160

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Filed Under: Percentage
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2 5360
Q:

The ratio of the speed of a boat downstream and speed of the stream is 9:1. If the speed of the current is 3 km per hr, find the distance travelled by the boat upstream in 5 hours.

A) 100 km B) 98 km
C) 109 km D) 105 km
 
Answer & Explanation Answer: D) 105 km

Explanation:

Let the speed of boat in still water is ‘x’ km/hr & that of stream is ‘y’ km/hr.
Then, ATQ
(x+y)/y = 9/1 9y = x + y
x = 8y
y = 3 km/hr
So, x = 24 km/hr
Upstream speed = 24-3 = 21 km/hr
Hence, distance travelled upstream in 5 hours = 21*5 = 105 km.

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Filed Under: Boats and Streams
Exam Prep: Bank Exams

8 5359
Q:

The age of Manisha and Sudeshna are in the ratio of 5 : 6 respectively. After 8 years the ratio  of their ages will be 7 : 8. What is the difference of their ages ?

A) 6 B) 4
C) 8 D) 10
 
Answer & Explanation Answer: B) 4

Explanation:

Let the age of Manisha and Sudeshna is 5x and 6x years respectively.

According to the given data,

5x+8/6x+8 = 7/8

42x + 56 = 40x + 64

x = 4

Required Difference of their ages = (6 × 4)  –  (5 × 4)

= 4 years.

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Filed Under: Problems on Ages
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Q:

In a bag which contains 40 balls, there are 18 red balls and some green and blue balls. If two balls are picked up from the bag without replacement, then the probability of the first ball being red and second being green is 3/26. Find the number of blue balls in the bag.

A) 16 B) 12
C) 10 D) 14
 
Answer & Explanation Answer: B) 12

Explanation:

Total balls = 40

Red balls = 18

Let green balls are x

Then, (18/40) × (

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Filed Under: Probability
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50 5354
Q:

A jeep travels a certain distance taking 6 hrs in forward journey, during the return journey increased speed 12km/hr takes the times 4 hrs. What is the distance travelled by the jeep is ?

A) 244 km B) 144 km
C) 444 km D) 344 km
 
Answer & Explanation Answer: B) 144 km

Explanation:

Given a jeep travels a certain distance taking 6 hrs in forward journey
During the return journey, it takes 4 hrs with an increased speed 12 km/hr
Let 'x' be the distance.
Now, speed is given by distance/time.
Here the difference between both speeds = 12

 x4 - x6 = 12

 3x - 2x12 = 12

 

=> x = 144 km

 

Therefore, the distance travelled by the jeep in forward or return journey is x = 144 km.

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Filed Under: Time and Distance
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3 5352
Q:

X and Y entered into partnership with Rs. 700 and Rs. 600 respectively. After another 3 months, X withdrew two- sevenths of his stock but after 3 months, he puts back three-fifths of what he had withdrawn. The total profit at the end of the year is Rs. 726. How much of this should X receive?

A) Rs. 336 B) Rs. 366
C) Rs. 633 D) Rs. 663
 
Answer & Explanation Answer: B) Rs. 366

Explanation:

Profit ratio X & Y = (700 × 3) + (700 × 5/7× 3) + (700× 5/7 + 200 × 3/5 )× 6 : 600 ×12
X:Y= 7320 : 7200= 183:180
∴ X’s share from profit = 183 × 726/(183+180) = Rs. 366.

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1 5344
Q:

5 years ago, the mother's age was 3 times of her son's age. 5 years hence, the ratio between the ages of mother and the son becomes 11:5. Find the mother's present age?

Answer

Let the present age's of mother be 'M' and that of her son be 'S'.


According to the given data in the question,


M - 5 = 3(S - 5)


F - 3S = -10  ...............(1)


Then given ,


M + 5 : S + 5 = 11 : 5 


=> 5M - 11S = 30 ..............(2)


 


From (1) & (2), we get


S = 20


Then by substituting S = 20 in (1) or (2), we get


M = 50.


 


Hence, the present age of mother is M = 50 years.

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Subject: Problems on Ages Exam Prep: AIEEE , Bank Exams , CAT , GATE
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