Quantitative Aptitude - Arithmetic Ability Questions

Q:

Concept of Efficiency

A can do a job in 12 days and B can do the same job in 6 days, in how many days working together they can complete the job?

Answer

A's 1 days work = 1/12 


B's 1 days work =1/6


Therefore, (A+B)'s 1 day's work= 1/12 + 1/6 = 1/4       


Therefore, Time taken by both to finish the whole work = 114 = 4 days


 


Alternatively :


Efficiency of A =100/12 =8.33%


Efficiency of B =100/6=16.66%


Combined efficiency of A and B both = 8.33+16.66=25%


Therefore, Time taken by both to finish the work (working together) =100/25= 4days

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Subject: Time and Work

3 6701
Q:

Find the cost of Rs. 4500, 8.5% stock at 4 premium?

A) 1400 B) 5000
C) 4000 D) 4680
 
Answer & Explanation Answer: D) 4680

Explanation:

Cost of Rs. 100 stock  = Rs. (100+4) = Rs.104

 

Cost of Rs. 4500 stock =Rs.104100×4500 = Rs. 4680

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Filed Under: Stocks and Shares

3 6697
Q:

Albert invested Rs. 8000 in a scheme for 2 years at compound interest rate 5% p.a. How much amount will Albert get on maturity of the fixed deposit  ?

A) Rs. 8840 B) Rs. 8800
C) Rs. 8810 D) None
 
Answer & Explanation Answer: D) None

Explanation:

Amount = 80001+51002

 

= 8000 x 21/20 x 21/20 

 

= Rs. 8820

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Filed Under: Compound Interest
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6 6697
Q:

The top and bottom of a tower were seen to be at angles of depression 30° and 60° from the top of a hill of height 100 m. Find the height of the tower ?

A) 42.2 mts B) 33.45 mts
C) 66.6 mts D) 58.78 mts
 
Answer & Explanation Answer: C) 66.6 mts

Explanation:

ht1488353450.jpg image

From above diagram
AC represents the hill and DE represents the tower

Given that AC = 100 m

angleXAD = angleADB = 30° (∵ AX || BD )
angleXAE = angleAEC = 60° (∵ AX || CE)

Let DE = h

Then, BC = DE = h, AB = (100-h) (∵ AC=100 and BC = h), BD = CE

tan 60°=AC/CE => √3 = 100/CE =>CE = 100/√3 ----- (1)

tan 30° = AB/BD => 1/√3 = 100−h/BD => BD = 100−h(√3)
∵ BD = CE and Substitute the value of CE from equation 1
100/√3 = 100−h(√3) => h = 66.66 mts

The height of the tower = 66.66 mts.

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Filed Under: Height and Distance
Exam Prep: AIEEE , Bank Exams , CAT , GATE , GRE
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17 6689
Q:

Anil purchases two books for Rs.100. He sells first at loss of 5% and second al 20% profit. If he gets Overall profit of 5% then what is cost of first book?

A) 58 B) 60
C) 55 D) 45
 
Answer & Explanation Answer: B) 60

Explanation:

-5-----------------------5-------------------20

5-(-5) = 10

20-5= 15

Ratio of cost price of book1 and book2 = 3:2 

Then cost price of book 1 is given by

(3/5) x 100 = Rs. 60.

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Filed Under: Profit and Loss
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20 6687
Q:

Two trains 85 m and 75 m long are running in same direction with speeds of 62 km/hr and 44 km/hr respectively. In what time will the first train cross the second train ?

A) 22 sec B) 32 sec
C) 42 sec D) 52 sec
 
Answer & Explanation Answer: B) 32 sec

Explanation:

Given that,

1st train speed = 62 km/hr 

2nd train speed  = 44 km/hr

Hence the relative speed of two trains is : 62-44 = 18 km/hr = 18×518 m/s = 5 m/s.

There fore, the first train crosses the second train i.e (85+75)mts of distance with a speed of 5m/s in, 

 

timedistancespeed = 85+755 = 32 sec.

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Filed Under: Time and Distance
Exam Prep: CAT
Job Role: Bank Clerk

8 6676
Q:

A girl want to read a complete book. She read 2/5 part of a book on 1st day, 34% on second day and remaining pages in next two days. On those two days she read equal number of pages. If she read 52 pages on last day, then find out total number of pages that the book contain ?

A) 400 B) 525
C) 325 D) 475
 
Answer & Explanation Answer: A) 400

Explanation:

Let the total number of pages in the book be 'x'.

From given data,

2x/5 + 34x/100 + 52 + 52 = x

 => 40x + 34x + 10400 = 100x

 => 26x = 10400

 => x = 400.

 Hence, total pages in the book are 400.

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Filed Under: Percentage
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7 6675
Q:

'K' cycled from A to B at 10 kmph and returned at the rate of 9 kmph. 'L' cycled both ways at 12 kmph. In the whole journey 'L' took 10 minutes less than 'K'. Find the distance between A and B ?

A) 32.1 km B) 15.23 km
C) 3.75 km D) 32.1 m
 
Answer & Explanation Answer: C) 3.75 km

Explanation:

Let 'd' be the distance between A and B
K -time = d/10 + d/9 = 19d/90 hours
L -time = 2d/12 = d/6 hours
We know that, 10 min = 1/6 hours
Thus, time difference between K and L is given as 10 minutes.
=> 19d/90 - d/6 = 1/6
=> (19d-15d)/90 = 1/6
=> 4d/90 = 1/6
Thus,
d= 15/4 km = 3.75 km.

hence the distance between A and B is 3.75 km.

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Filed Under: Time and Distance
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3 6670