Free Practice Questions for Competitive Exams, Interviews, Certifications

Q:

A problem is given to three students whose chances of solving it are 1/2, 1/3 and 1/4 respectively. What is the probability that the problem will be solved?

A) 1/4	B) 1/2
C) 3/4	D) 7/12

Answer & Explanation Answer: C) 3/4

Explanation:

Let A, B, C be the respective events of solving the problem and $A, B, C$ be the respective events of not solving the problem. Then A, B, C are independent event

$∴ A, B, C$ are independent events

Now, P(A) = 1/2 , P(B) = 1/3 and P(C)=1/4

$P (A) = \frac{1}{2}, P (B) = \frac{2}{3}, P (C) = \frac{3}{4}$

$∴$ P( none solves the problem) = P(not A) and (not B) and (not C)

= $P (A \cap B \cap C)$

= $P (A) P (B) P (C)$ $[∵ A, B, C a r e I n d e p e n d e n t]$

= $\frac{1}{2} \times \frac{2}{3} \times \frac{3}{4}$

= $\frac{1}{4}$

Hence, P(the problem will be solved) = 1 - P(none solves the problem)

= $1 - \frac{1}{4}$ = 3/4

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Filed Under: Probability
Exam Prep: AIEEE , Bank Exams , CAT , GATE
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899 195454

Q:

Two numbers are respectively 20% and 50% more than a third number. The ratio of the two numbers is:

A) 2:5	B) 3:5
C) 4:5	D) 5:4

Answer & Explanation Answer: C) 4:5

Explanation:

Let the third number be x.

Then, first number = 120% of x =120x/100 = 6x/5

Second number =150% of x = 150x/100 = 3x/2

Ratio of first two numbers = 6x/5 : 3x/2 = 12x : 15x = 4 : 5

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Filed Under: Ratios and Proportions

559 181349

Q:

The Hardest Logic Puzzle Ever?

If a giraffe has two eyes, a monkey has two eyes, and an elephant has two eyes, how many eyes do we have?

A) 3	B) 4
C) 1	D) 2

Answer & Explanation Answer: B) 4

Explanation:

4 eyes.

Here in the question, it is asked how many Eyes We have so that means here the person who has asked the question is also including the person who is suppose to give the answer. In a clear understanding, the Conversation is happening between 2 people 1st who asked the question and 2nd to whom it has been asked, which means there are 4 eyes.

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Filed Under: Logic Puzzles
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1305 172838

Q:

Crack the code & Unlock the Key ?

A) 062	B) 602
C) 042	D) 204

Answer & Explanation Answer: C) 042

Explanation:

From all the hints given,

only 042 satisfies and it unlocks the key.

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Filed Under: Number Puzzles
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1008 164934

Q:

In a certain code language COMPUTER is written as RFUVQNPC. How will MEDICINE be written in that code language?

A) MFEDJJOE	B) EOJDEJFM
C) MFEJDJOE	D) EOJDJEFM

Answer & Explanation Answer: D) EOJDJEFM

Explanation:

- There are 8 letters in the word.

- The coded word can be obtained by taking the immediately following letters of word, expect the first and the last letters of the given word but in the reverse order. That means, in the coded form the first and the last letters have been interchanged while the remaining letters are coded by taking their immediate next letters in the reverse order.

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Filed Under: Coding and Decoding

2433 163014

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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Filed Under: Alphabet Test

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Q:

Find the odd man out.

2, 5, 10, 17, 26, 37, 50, 64

A) 50	B) 37
C) 26	D) 64

Answer & Explanation Answer: D) 64

Explanation:

(1*1)+1 , (2*2)+1 , (3*3)+1 , (4*4)+1 , (5*5)+1 , (6*6)+1 , (7*7)+1 , (8*8)+1

But, 64 is out of pattern.

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Filed Under: Odd Man Out

102 151793

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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Filed Under: Percentage

771 150966

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