Aptitude and Reasoning Questions

Q:

A student multiplied a number by 3/5 instead of 5/3, What is the percentage error in the calculation ?

A) 54 % B) 64 %
C) 74 % D) 84 %
 
Answer & Explanation Answer: B) 64 %

Explanation:

Let the number be x.

Then, ideally he should have multiplied by  x by 5/3. Hence Correct result was x * (5/3)= 5x/3. 

 

By mistake he multiplied x by 3/5 . Hence the result with error  = 3x/5 

Then, error = (5x/3 - 3x/5) = 16x/15 

Error %  = (error/True vaue) * 100 = [(16/15) * x/(5/3) * x] * 100 = 64 %

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751 149927
Q:

If you write down all the numbers from 1 to 100, then how many times do you write 3 ?

A) 11 B) 18
C) 20 D) 21
 
Answer & Explanation Answer: C) 20

Explanation:

Clearly, From 1 to 100, there are ten numbers with 3 as the unit's digit - 3, 13, 23, 33, 43, 53, 63, 73, 83, 93 and ten numbers with 3 as the ten's digit - 30, 31, 32, 33, 34, 35, 36, 37, 38, 39.

 

So, required number = 10 + 10 = 20.

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733 58783
Q:

A bag contains 6 white and 4 black balls .2 balls are drawn at random. Find the probability that they are of same colour.

A) 1/2 B) 7/15
C) 8/15 D) 1/9
 
Answer & Explanation Answer: B) 7/15

Explanation:

Let S be the sample space

 

Then n(S) = no of ways of drawing 2 balls out of (6+4) =10C2 10 =10*92*1 =45

 

Let E = event of getting both balls of same colour

 

Then,n(E) = no of ways (2 balls out of six) or (2 balls out of 4)

 

                =6C2+4C2 = 6*52*1+4*32*1= 15+6 = 21

 

Therefore, P(E) = n(E)/n(S) = 21/45 = 7/15

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722 127548
Q:

Two bus tickets from city A to B and three tickets from city A to C cost Rs. 77 but three tickets from city A to B and two tickets from city A to C cost Rs. 73. What are the fares for cities B and C from A ?

A) Rs. 4, Rs. 23 B) Rs. 13, Rs. 17
C) Rs. 15, Rs. 14 D) Rs. 17, Rs. 13
 
Answer & Explanation Answer: B) Rs. 13, Rs. 17

Explanation:

Let Rs. x be the fare of city B from city A and Rs. y be the fare of city C from city A.

Then, 2x + 3y = 77 ...(i) and

3x + 2y = 73 ...(ii)

Multiplying (i) by 3 and (ii) by 2 and subtracting, we get: 5y = 85 or y = 17.

Putting y = 17 in (i), we get: x = 13.

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Q:

Find the number of triangles in the given figure.

A) 28 B) 32
C) 36 D) 40
 
Answer & Explanation Answer: C) 36

Explanation:

  

The simplest triangles are AML, LRK, KWD, DWJ, JXI, IYC, CYH, HTG, GOB, BOF, FNE and EMA i.e. 12 in number.

The triangles composed of two components each are AEL, KDJ, HIC and FBG i.e. 4 in number.

The triangles composed of three components each are APF, EQB, BQH, GVC, CVJ, IUD, DUL and KPA i.e. 8 in number.

The triangles composed of six components each are ASB, BSG, CSD, DSA, AKF, EBH, GGJ and IDL i.e. 8 in number.

The triangles composed of twelve components each are ADB, ABC, BCD and CDA i.e. 4 in number.

Total number of triangles in the figure = 12 + 4 + 8 + 8 + 4 = 36.

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692 64120
Q:

In a certain code language,

(A) ‘pit na som’ means ‘bring me water’

(B) ‘na jo tod’ means ‘water is life’

(C) ‘tub od pit’ means 'give me toy’

(D) ‘jo lin kot’ means ‘life and death’

Which of the following represents 'is' in that language ?

A) jo B) na
C) tod D) lin
 
Answer & Explanation Answer: C) tod

Explanation:

Justification:   

In statements A and B, the common code word is 'na' and the common word is 'water'.

So, 'na' means 'water'.

In statements B and D, the common code word is 'jo' and the common word is 'life'.
So, 'jo' means 'life'.
Thus, in statements B, 'tod' represents 'is'.

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691 49678
Q:

In a row of boys, If A who is 10th from the left and B who is 9th from the right interchange their positions, A becomes 15th from the left. How many boys are there in the row ?

A) 23 B) 31
C) 27 D) 28
 
Answer & Explanation Answer: A) 23

Explanation:

Clearly, A’s new position is 15th from the left. But this is the same as B’s earlier position which is 9th from the right.

 

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689 86925
Q:

The value of a machine depreciates at the rate of 10% every year. It was purchased 3 years ago. If its present value is Rs. 8748, its purchase price was :

A) 10000 B) 12000
C) 14000 D) 16000
 
Answer & Explanation Answer: B) 12000

Explanation:

Purchase price = Rs.87481-101003 = Rs. [8748 * (10/9) * (10/9 )* (10/9)] = Rs.12000

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685 95059