Aptitude and Reasoning Questions

Q:

Two cards are drawn at random from a pack of 52 cards.what is the probability that either both are black or both are queen?

A) 52/221 B) 55/190
C) 55/221 D) 19/221
 
Answer & Explanation Answer: C) 55/221

Explanation:

We have n(s) =52C2 52 = 52*51/2*1= 1326. 

Let A = event of getting both black cards 

     B = event of getting both queens 

A∩B = event of getting queen of black cards 

n(A) = 52*512*1 = 26C2 = 325, n(B)= 26*252*1= 4*3/2*1= 6  and  n(A∩B) = 4C2 = 1 

P(A) = n(A)/n(S) = 325/1326;

P(B) = n(B)/n(S) = 6/1326 and 

P(A∩B) = n(A∩B)/n(S) = 1/1326 

P(A∪B) = P(A) + P(B) - P(A∩B) = (325+6-1) / 1326 = 330/1326 = 55/221

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339 119314
Q:

A bag contains 4 white, 5 red and 6 blue balls. Three balls are drawn at random from the bag. The probability that all of them are red, is:

A) 2/91 B) 1/22
C) 3/22 D) 2/77
 
Answer & Explanation Answer: A) 2/91

Explanation:

Let S be the sample space.

Then, n(S) = number of ways of drawing 3 balls out of 15 = 15C3  =15*14*133*2*1= 455.  

Let E = event of getting all the 3 red balls.

 n(E) = 5C3 = 5*42*1 = 10.

 => P(E) = n(E)/n(S) = 10/455 = 2/91.

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189 115685
Q:

It was Sunday on Jan 1, 2006. What was the day of the week Jan 1, 2010?

A) Monday B) Friday
C) Sunday D) Tuesday
 
Answer & Explanation Answer: B) Friday

Explanation:

On 31st December, 2005 it was Saturday. 

Number of odd days from 2006 to 2009 = (1 + 1 + 2 + 1) = 5 days. 

 

On 31st December 2009, it was Thursday.

Thus, on 1st Jan, 2010 it is Friday

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628 113379
Q:

Find the missing number in the following series?

3, 5, 5, 19, 7, 41, 9, ?

A) 71 B) 61
C) 79 D) 69
 
Answer & Explanation Answer: A) 71

Explanation:

Fiest series : 3, 5, 7, 9

Second series : 5, 19, 41, ?

 Difference of Second series are 14, 22, 30 etc

Next term is 41+30 i.e equal to 71

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1035 112900
Q:

A shopkeeper cheats to the extent of 10% while buying and selling, by using false weights. His total gain is.

A) 20% B) 21%
C) 22% D) 23%
 
Answer & Explanation Answer: B) 21%

Explanation:

Gain % = 100+common gain %2100-100%           

 

           =100+102100-100

 

            = 21%

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614 112167
Q:

In a lottery, there are 10 prizes and 25 blanks. A lottery is drawn at random. What is the probability of getting a prize?

A) 2/7 B) 5/7
C) 1/5 D) 1/2
 
Answer & Explanation Answer: A) 2/7

Explanation:

Total number of outcomes possible, n(S) = 10 + 25 = 35

 

Total number of prizes, n(E) = 10

 P(E)=n(E)n(S)=1035=27

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253 112004
Q:

How many 4's are there preceded by 7 but not followed by 3?

5  9  3  2  1  7  4  2  6  9  7  4  6  1  3  2  8  7  4  1  3  8  3  2  5  6  7  4  3  9  5  8  2  0  1  8  7  4  6  3

A) Four B) Three
C) Six D) Five
 
Answer & Explanation Answer: A) Four

Explanation:

7  4  2

7  4  6

7  4  1

7  4  6

 

Only at these placees 4 is preceded by 7 but not followed by 3

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976 110535
Q:

Find the odd man out.

6, 9, 15, 21, 24, 28, 30

A) 28 B) 21
C) 24 D) 30
 
Answer & Explanation Answer: A) 28

Explanation:

Each of the numbers except 28, is a multiple of 3.

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86 107193