Last updated at March 8, 2017 by Teachoo

Transcript

Ex 7.1, 4 How many 5–digit telephone numbers can be constructed using the digits 0 to 9 if each number starts with 67 and no digit appears more than once? The telephone number is of 5 digits and first 2 numbers are 6 and 7 Hence number is of the form Digits between 0 to 9 = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 Total number of digit between 0 to 9 = 10 1st & 2nd place is fix 3rd place – After fixing 67 only 8ways to (10 – 2) fill 3rd place . 4th place – After fixing 6, 7, & 3rd place & 4th place, only 7ways (10 – 3) 5th place – After fixing 6, 7, 3rd place & 4th place, only 6 ways (10 – 4) to fill 5th place No. of telephone number that can be formed = 8 × 7 × 6 = 336

Ex 7.1,6
Important

Ex 7.1,4 Important You are here

Example 13 Important

Example 16 Important

Ex 7.3,3 Important

Ex 7.3,6 Important

Ex 7.3,10 Important

Example 19 Important

Ex 7.4, 6 Important

Ex 7.4, 8 Important

Example 23 Important

Misc 3 Important

Misc 4 Important

misc 7 Important

Misc 10 Important

Misc 11 Important

Class 11

Important Question for exams Class 11

- Chapter 1 Class 11 Sets
- Chapter 2 Class 11 Relations and Functions
- Chapter 3 Class 11 Trigonometric Functions
- Chapter 4 Class 11 Mathematical Induction
- Chapter 5 Class 11 Complex Numbers
- Chapter 6 Class 11 Linear Inequalities
- Chapter 7 Class 11 Permutations and Combinations
- Chapter 8 Class 11 Binomial Theorem
- Chapter 9 Class 11 Sequences and Series
- Chapter 10 Class 11 Straight Lines
- Chapter 11 Class 11 Conic Sections
- Chapter 12 Class 11 Introduction to Three Dimensional Geometry
- Chapter 13 Class 11 Limits and Derivatives
- Chapter 14 Class 11 Mathematical Reasoning
- Chapter 15 Class 11 Statistics
- Chapter 16 Class 11 Probability

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He provides courses for Mathematics from Class 9 to 12. You can ask questions here.