Formation of Number
(Q).How many 5 digit numbers are there?
Solution:-
= 9×10×10×10×10
= 90000 Answer
(Q). How many 4 digit numbers can be formed from the digit 0, 1, 3, 6, 7, 9
(i) if repetition of digit is not allowed
(ii) if repetition of digit is allowed
Solution:-
(Q). Find the number of 5 digit numbers that can be formed from the digits: 6 6 6 9 9.
Solution:- =
= 10 Answer
(Q). Find the nuumber of 5 digit numbers that can be formed from the digit 1 1 6 6 6 such that the number is divisible by 4.
Solution:-
A number is divisible by 4 ⇒ if last two digits of the number is divisible by 4
Hence
=
= 3 Answer