Aptitude and Reasoning Questions

Q:

Two boxes contain 4 and 16 balls respectively. Two balls in the first box and four in the second, are black. If a box is chosen randomly and two balls are drawn at random from it, what is the
probability that at least one ball is black if the ball is not replaced?

A) 11/20 B) 43/120
C) 77/120 D) 9/20
 
Answer & Explanation Answer: C) 77/120

Explanation:

At least one black can be chosen in two ways from each box:
Now, probability of choosing at least one black ball from first box 

= 1/2 × [ (2C1× 2C1)/4C2 + 2C2/ 4C2 ]= 5/12

Probability of choosing at least one black ball from 2nd box
= 1/2 × [(4C1×12C1)/16C2 + 4C2/ 16C2] = 9/40

Final probability

= 5/12 + 9/40 = (50 + 27)/120 = 77/120

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5 4903
Q:

Find the odd man out 1 4 9 16 22 36?

A) 9 B) 16
C) 22 D) 36
 
Answer & Explanation Answer: C) 22

Explanation:

In the given series 1 4 9 16 22 36

1 = 1 x 1 

4 = 2 x 2

9 = 3 x 3

16 = 4 x 4

25 = 5 x 5 (Not 22)

36 = 6 x 6

 

Hence, the odd man in the series is 22.

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Filed Under: Odd Man Out
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13 4903
Q:

Choose the pair in which the words are differently related?

A) Man : Garage B) Cow : Shed
C) Pig : Sty D) Horse : Stable
 
Answer & Explanation Answer: A) Man : Garage

Explanation:

In all other pairs, second is the place of stay of the first.

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Filed Under: Classification

27 4901
Q:

If 3a=4b=6c and a+b+c=2729, then a2+b2+c2 =?

A) 81 B) 83
C) 87 D) None of these
 
Answer & Explanation Answer: C) 87

Explanation:

4b=6cb=32c    and   3a=4ba=43b=43(32c)=2c 

a+b+c=2729   2c+32c+c=2729  c=629

 

 a2+b2+c2=(a+b+b)2-2(ab+bc+ca) 

 

=(2729)2-22c×32c+32c×c+c×2c 

 

 =729×29-2×132 c2

= 87

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12 4895
Q:

How many such pair of letters are there in the word ‘TROUBLED’ which have as many letters between them in the word as they have between them in the English alphabet?

A) 2 B) 3
C) 4 D) 5
 
Answer & Explanation Answer: A) 2

Explanation:

Hence there are two pairs

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13 4894
Q:

There are 3 sections with 5 questions each. If four questions are selected from each section, the chance of getting different questions is ?

A) 1000 B) 625
C) 525 D) 125
 
Answer & Explanation Answer: D) 125

Explanation:

Methods for selecting 4 questions out of 5 in the first section = 5 x 4 x 3 x 2 x 1/4 x 3 x 2 x 1 = 5. Similarly for other 2 sections also i.e 5 and 5


So total methods = 5 x 5 x 5 = 125.

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Filed Under: Permutations and Combinations
Exam Prep: GRE , GATE , CAT , Bank Exams , AIEEE
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4 4893
Q:

Find the lowest common multiple of 24, 36 and 40?

A) 360 B) 420
C) 240 D) 120
 
Answer & Explanation Answer: A) 360

Explanation:

To find the LCM of 24, 36 and 40

24 = 2 x 2 x 2 x 3

36 = 2 x 2 x 3 x 3

40 = 2 x 2 x 2 x 5 

Now, LCM of 24, 36 and 40 = 2 x 2 x 2 x 3 x 3 x 5

= 8 x 9 x 5

= 72 x 5

= 360

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Filed Under: HCF and LCM
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19 4889
Q:

Three of the following four are alike in a certain way and hence form a group. Which is the one that does not belong to that group?

A) EBA B) XUT
C) TQP D) JFE
 
Answer & Explanation Answer: D) JFE

Explanation:

In all other groups, the third and second letters are consecutive and first letter is three steps ahead of the second.

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Filed Under: Classification

43 4889