Quantitative Aptitude - Arithmetic Ability Questions

Q:

What is the common ratio of the following geometric sequence?

4, 2, 1, 0.5, 0.25, 0.125,...

A) 0.5 B) -1
C) 1.5 D) -0.5
 
Answer & Explanation Answer: A) 0.5

Explanation:

In mathematics, a geometric progression, also known as a geometric sequence, is a sequence of numbers where each term after the first is found by multiplying the previous one by a fixed, non-zero number called the common ratio.

 

Herein the given sequence, 4, 2, 1, 0.5, 0.25, 0.125,...

Common Ratio r = 2/4 = 1/2 = 0.5/1 = 0.25/0.5 = 0.125/0.25 == 0.5.

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Filed Under: Problems on Numbers
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3 51874
Q:

The percentage profit earned by selling an article for Rs. 1920 is equal to the percentage loss incurred by selling the same article for Rs. 1280. At what price should the article be sold to make 25% profit?

A) Rs. 2000 B) Rs. 2200
C) Rs. 2400 D) Data inadequate
 
Answer & Explanation Answer: A) Rs. 2000

Explanation:

Let C.P. be Rs. x.

 

Then,= >1920-xx*100=x-1280x*100

 

=>  1920 - x = x - 1280

 

=>  2x = 3200

 

=>  x = 1600

 

 Required S.P. = 125% of Rs. 1600 =Rs(125/100*1600) = Rs2000

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Filed Under: Profit and Loss

318 51840
Q:

A number is decreased by 10% and then increased by 10%.  The number so obtained is 10 less than the original number. What was the oiginal number ? 

A) 1000 B) 2000
C) 3000 D) 4000
 
Answer & Explanation Answer: A) 1000

Explanation:

Let the original number be x.

 

Final number obtained = 110% of (90% of x) =(110/100 * 90/100 * x) = (99/100)x. 

 

x-(99/100)x=10

=> x =1000

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Filed Under: Percentage

142 51474
Q:

In how many different ways can the letters of the word 'OPTICAL' be arranged so that the vowels always come together?

A) 360 B) 700
C) 720 D) 120
 
Answer & Explanation Answer: C) 720

Explanation:

The word 'OPTICAL' contains 7 different letters.

When the vowels OIA are always together, they can be supposed to form one letter.

Then, we have to arrange the letters PTCL (OIA).

Now, 5 letters can be arranged in 5! = 120 ways.

The vowels (OIA) can be arranged among themselves in 3! = 6 ways.

Required number of ways = (120 x 6) = 720.

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51 51422
Q:

50 men took a dip in a water tank 40 m long and 20 m broad on a religious day. If the average displacement of water by a man is 4 cu.m , then the rise in the water level in the tank will be:

A) 20 cm B) 25 cm
C) 35 cm D) 50 cm
 
Answer & Explanation Answer: B) 25 cm

Explanation:

Total volume of water displaced =(4 x 50) cu.m = 200 cu.m

 

Rise in water level = 20040×20=0.25m = 25cm

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64 51170
Q:

What will come in place of the question mark (?) in the following number series?

17, 98, 26, 89, 35, ?

A) 80 B) 75
C) 67 D) 53
 
Answer & Explanation Answer: A) 80

Explanation:

1. Ans. A.
98 = 17 + 81
26 = 98 – 72
89 = 26 + 63
35 = 89 – 54
? = 35 + 45, i.e. ? = 80

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2 51094
Q:

The G.C.D of 1.08, 0.36 and 0.9 is

A) 0.03 B) 0.9
C) 0.18 D) 0.108
 
Answer & Explanation Answer: C) 0.18

Explanation:

Given numbers are 1.08 , 0.36 and 0.90

 H.C.F of 108, 36 and 90 is 18                  [  G.C.D is nothing but H.C.F]

 Therefore, H.C.F of given numbers = 0.18                 

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Filed Under: HCF and LCM

138 51078
Q:

If 20 men can build a wall 56 meters long in 6 days , what length of  a similar wall can be  built by 35 men in 3 days?

A) 46 B) 47
C) 48 D) 49
 
Answer & Explanation Answer: D) 49

Explanation:

Let the required length be x meters

 More men, More length built     (Direct proportion) 

Less days, Less length built      (Direct Proportion)

Men20:35Days6 : 3 56 :x 

=> (20 x 6 x X)=(35 x 3 x 56) 

=> x = 49 

Hence, the required length is 49 m.

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Filed Under: Chain Rule

156 51057