A. 120

**B. 720**

C. 4320

D. 2160

# Permutations and Combinations

## A person ordered 5 pairs of black socks and some pairs of brown socks. The price of a black pair was thrice that of a brown pair while preparing the bill the bill clerk inter-changed the number of black and brown pairs by mistake which increased the bill by 100% what was the number of pair of brown socks in the original order?

A. 10

B. 15

C. 20

**D. 25**

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## A group consists of 4 men, 6 women and 5 children. In how many ways can 3 men, 2 women and 3 children selected from the given group?

A. 300

B. 450

**C. 600**

D. 750

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## Three dice (each having six faces with each face having one number from 1 or 6) are ralled. What is the number of possible outcomes such that atleast one dice shows the number 2?

A. 36

B. 81

**C. 91**

D. 116

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## In a question paper, there are four multiple choice type questions, each question has five choices with only one choice for it’s correct answer. What is the total number of ways in which a candidate will not get all the four answers correct?

A. 19

B. 120

**C. 624**

D. 1024

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## How many four digit numbers can be formed using the digits {1, 3, 4, 5, 7,9}(repetition of digits is not allowed)?

**A. 360**

B. 60

C. 300

D. 180

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## Find the number of ways of arranging the letters of the word “MATERIAL” such that all the vowels in the word are to come together?

A. 720

**B. 1440**

C. 1860

D. 2160

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## How many three letter words are formed using the letters of the word TIME?

A. 12

B. 20

C. 16

**D. 24**

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## In how many different ways can four books A, B, C and D be arranged one above another in a vertical order such that the books A and B are never in continuous position?

A. 9

**B. 12**

C. 14

D. 18

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## A group of 10 representatives is to be selected out of 12 seniors and 10 juniors. In how many different ways can the group be selected, if it should have 5 seniors and 5 juniors?

A. ¹²C₅ * 10

B. ¹²C₇ * 10

**C. ¹²C₇ * ¹⁰C₅**

D. 12 * ¹⁰C₅

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