NCERT Exercise 7.3

Meaning of Permutations, Derivation for rule of Permutations

Question 1. How many 3-digit numbers can be formed by using the digits 1 to 9 if no digit is repeated?

Question 2. How many 4-digit numbers are there with no digit repeated?

Question 3. How many 3-digit even numbers can be made using the digits 1, 2, 3, 4, 6, 7, if no digit is repeated?

Question 4. Find the number of 4-digit numbers that can be formed using the digits 1, 2, 3, 4, 5 if no digit is repeated. How many of these will be even?

Question 5. From a committee of 8 persons, in how many ways can we choose a chairman and a vice chairman assuming one person can not hold more than one position?

Question 6.  Find if $$^{n-1}P_3 : ^nP_4 = 1 : 9$$

Question 7.  Find r if
(i) $$^5P_r = 2 ^6P_{r-1}$$
(ii) $$^5P_r = ^6P_{r-1}$$