Question

How many 5 digit odd numbers can be formed using the digits 0-8, if no digit is to occur more than once in any number

Answer 1

0-8 there are 9 digits,

for forming 5 digit odd no. a unit place of such no. is odd. Total odd no. from 0-8 are 1,3,5,7 (4 digit) so unit place is consist by any of these no.

5th no. of 5 digit no. is must be from 1-8 because 0 is not considered so total no. at 5th position are = 7 (except 0 and any odd no. which is on unit place.)

Now at 2nd 3rd and 4th place no. are 7,6,5 so total no. are formed = 8*7*6*5*4 = 6720