Achieve Indian Airforce Agniveer Vayu Mathematics Practice Book>Chapter 6 - Permutations and Combinations>Exercise>Q 22

MEDIUM

Agniveer Vayu

IMPORTANT

Earn 100

The number of five digit telephone numbers having at least one of their digits repeated is

50% studentsanswered this correctly

Important Questions on Permutations and Combinations

EASY

Agniveer Vayu

IMPORTANT

Achieve Indian Airforce Agniveer Vayu Mathematics Practice Book>Chapter 6 - Permutations and Combinations>Exercise>Q 23

In an examination there are three multiple choice questions and each question has

5

choices. Number of ways in which a student can fail to get all answer correct is

EASY

Agniveer Vayu

IMPORTANT

Achieve Indian Airforce Agniveer Vayu Mathematics Practice Book>Chapter 6 - Permutations and Combinations>Exercise>Q 24

The sum of the digits at the

10^{t h}

place of all numbers formed with the help of

2, 4, 5, 7

taken all at a time is

EASY

Agniveer Vayu

IMPORTANT

Achieve Indian Airforce Agniveer Vayu Mathematics Practice Book>Chapter 6 - Permutations and Combinations>Exercise>Q 25

The number of

10

digit number that can be written by using the digits

2

and

3

is

MEDIUM

Agniveer Vayu

IMPORTANT

Achieve Indian Airforce Agniveer Vayu Mathematics Practice Book>Chapter 6 - Permutations and Combinations>Exercise>Q 26

If

P_{r}

stands for

^{r} P_{r}

then the sum of the series

1 + P_{1} + 2 P_{2} + 3 P_{3} + \dots + n P_{n}

is

EASY

Agniveer Vayu

IMPORTANT

Achieve Indian Airforce Agniveer Vayu Mathematics Practice Book>Chapter 6 - Permutations and Combinations>Exercise>Q 27

The number of different ways in which

8

persons can stand in a row so that between two particular persons

A

and

B

there are always two persons, is

EASY

Agniveer Vayu

IMPORTANT

Achieve Indian Airforce Agniveer Vayu Mathematics Practice Book>Chapter 6 - Permutations and Combinations>Exercise>Q 28

The number of different signals which can be given from

6

flags of different colours taking one or more at a time

MEDIUM

Agniveer Vayu

IMPORTANT

Achieve Indian Airforce Agniveer Vayu Mathematics Practice Book>Chapter 6 - Permutations and Combinations>Exercise>Q 29

The number of ways of arranging

6

players to throw the cricket ball so that the oldest player may not throw first is

MEDIUM

Agniveer Vayu

IMPORTANT

Achieve Indian Airforce Agniveer Vayu Mathematics Practice Book>Chapter 6 - Permutations and Combinations>Exercise>Q 30

Number of four-digit positive integers, if the product of their digits is divisible by

3

are