Aptitude and Reasoning Questions

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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593 100932
Q:

If 20% of a = b, then b% of 20 is the same as :

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

Explanation:

20% of a = b 

=> (20/100) * a = b 

 b% of 20 =(b/100) x 20 = [(20a/100)  / 100] x 20= 4a/100 = 4% of a.

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864 91173
Q:

How many pairs of letters are there in the word " CASTRAPHONE" which have as many letters between them in the word as in the alphabet?

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

Explanation:

Looking into the alphabets there are six such pairs namely ON, HONE, ST, TRAPHO, TRAPHON, RAP.

1. ON  - NO

2. HONE - EFGH

3. ST - ST

4. TRAPHO - OPQRST

5. TRAPHON - NOPQRST

6. RAP - PQR

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1333 87885
Q:

A is B's sister. C is B's mother. D is C's father. E is D's mother. Then, how is A related to D?

A) Grandfather B) Grandmother
C) Daughter D) Granddaughter
 
Answer & Explanation Answer: D) Granddaughter

Explanation:

A is the sister of B and B is the daughter of C.

So, A is the daughter of C. Also, D is the father of C.

So, A is the granddaughter of D. 

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2593 85106
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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403 81087
Q:

A trader mixes 26 kg of rice at Rs. 20 per kg with 30 kg of rice of other variety at Rs. 36 per kg and sells the mixture at Rs. 30 per kg. His profit percent is:

A) No profit, no loss B) 5%
C) 8% D) 10%
 
Answer & Explanation Answer: B) 5%

Explanation:

C.P. of 56 kg rice = Rs. (26 x 20 + 30 x 36) = Rs. (520 + 1080) = Rs. 1600.

 

S.P. of 56 kg rice = Rs. (56 x 30) = Rs. 1680.

 

Gain =(80/1600*100) % = 5%

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622 79283
Q:

Fresh fruit contains 68% water and dry fruit contains 20% water. How much dry fruit can be obtained from 100 kg of fresh fruits ?

A) 20 B) 30
C) 40 D) 50
 
Answer & Explanation Answer: C) 40

Explanation:

The fruit content in both the fresh fruit and dry fruit is the same.

 

Given, fresh fruit has 68% water.so remaining 32% is fruit content. weight of fresh fruits is 100kg

 

Dry fruit has 20% water.so remaining 80% is fruit content.let weight if dry fruit be y kg.

 

Fruit % in freshfruit = Fruit% in dryfruit 

 

Therefore, (32/100) x 100 = (80/100 ) x y 

 

we get, y = 40 kg.

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878 77873
Q:

A clock is set right at 8 a.m. The clock gains 10 minutes in 24 hours will be the true time when the clock indicates 1 p.m. on the following day?

A) 48 min. past 12. B) 46 min. past 12.
C) 45 min. past 12. D) 47 min. past 12.
 
Answer & Explanation Answer: A) 48 min. past 12.

Explanation:

Time from 8 a.m. on a day to 1 p.m. on the following day = 29 hours. 

24 hours 10 min. of this clock = 24 hours of the correct clock. 

1456 hrs of this clock = 24 hours of the correct clock. 

29 hours of this clock = 24*6145*29 hrs of the correct clock 

= 28 hrs 48 min of the correct clock. 

Therefore, the correct time is 28 hrs 48 min. after 8 a.m. 

This is 48 min. past 12.

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