Quantitative Aptitude - Arithmetic Ability Questions

Q:

The product of two numbers is 2028 and their H.C.F. is 13. The number of such pairs is:

A) 1 B) 2
C) 3 D) 4
 
Answer & Explanation Answer: B) 2

Explanation:

Let the numbers 13a and 13b.

Then, 13a x 13b = 2028

=>ab = 12.

Now, the co-primes with product 12 are (1, 12) and (3, 4).

[Note: Two integers a and b are said to be coprime or relatively prime if they have no common positive factor other than 1 or, equivalently, if their greatest common divisor is 1 ]

So, the required numbers are (13 x 1, 13 x 12) and (13 x 3, 13 x 4).

Clearly, there are 2 such pairs.

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Filed Under: HCF and LCM

231 68817
Q:

An air conditioner can cool the hall in 40 miutes while another takes 45 minutes to cool under similar conditions. If both air conditioners are switched on at same instance then how long will it take to cool the room approximately ?

A) 18 minutes B) 19 minutes
C) 22 minutes D) 24 minutes
 
Answer & Explanation Answer: C) 22 minutes

Explanation:

Let the two conditioners be A and B

 

'A' cools at 40min

 

'B' at 45min

 

Together = (a x b)/(a + b)

= (45 x 40)/(45 + 40)

= 45 x 40/85

= 21.1764

= 22 min (approx).

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Filed Under: Time and Work
Exam Prep: GRE , GATE , CAT , Bank Exams , AIEEE
Job Role: Bank PO , Bank Clerk

94 68738
Q:

Simplify : 5x - 2x(x-1)

 

A) 3x-2 B) 3x+2
C) 7x+2x2 D) 7x-2x2
 
Answer & Explanation Answer: D) 7x-2x2

Explanation:
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Filed Under: Simplification
Exam Prep: Bank Exams

0 68672
Q:

What approximate value will come in place of the question mark(?) in the below question?

(47% of 1442  - 36% of 1412) + 63 = ?

A) 4 B) 5
C) 3 D) 6
 
Answer & Explanation Answer: C) 3

Explanation:
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Filed Under: Problems on Numbers

25 68314
Q:

Solve the following :

38 - (60 ÷ 5 x 16 - 8 ÷ 2 ÷ 3) =?

 

A) 22 B) 29
C) 30 D) 37
 
Answer & Explanation Answer: A) 22

Explanation:
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Filed Under: Simplification
Exam Prep: Bank Exams

2 68196
Q:

A man's speed with the current is 15 km/hr and the speed of the current is 2.5 km/hr. The man's speed against the current is :

A) 9.5 km/hr B) 10 km/hr
C) 10.5 km/hr D) 11 km/hr
 
Answer & Explanation Answer: B) 10 km/hr

Explanation:

Man's rate in still water = (15 - 2.5) km/hr = 12.5 km/hr.

Therefore,  Man's rate against the current = (12.5 - 2.5) = 10 km/hr.

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Filed Under: Problems on Trains
Exam Prep: CAT
Job Role: Bank PO

109 68028
Q:

A mixture contains alcohol and water in the ratio 4 : 3. If 5 liters of water is added to the mixture, the ratio becomes 4: 5. Find the quantity of alcohol in the given mixture.

A) 10 B) 12
C) 15 D) 18
 
Answer & Explanation Answer: A) 10

Explanation:

Let the quantity of alcohol and water be 4x litres and 3x litres respectively

 

4x/(3x+5) = 4/5 

 

20x = 4(3x+5)

 

8x = 20

 

x = 2.5

 

Quantity of alcohol = (4 x 2.5) litres = 10 litres.

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Filed Under: Ratios and Proportions

347 67882
Q:

Find the value of 

n+3n2+9n4+......

A) 0 B) 1
C) 2 D) infinity
 
Answer & Explanation Answer: D) infinity

Explanation:
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Filed Under: Simplification

4 67788