Question

how many 5 digit odd numbers are there donot contain the digits 3 or 6 or9

Answer 1

There are 6 choices for the first digit (since it can't be 0, 3, 6 or 9). For each of these, there are 7 choices for the second digit, then 7 choices for the third, and then 7 for the fourth. In each case, the final digit can only be 0 or 2 or 4 or 8 (so 4 choices).

Hence, the number of 5 digit numbers = 6 x 7 x 7 x 7 x 4 = 8232.

Answer 2

Answer: 16807

Step-by-step explanation:

Total digits in number system : 0,1,2,3,4,5,6,7,8,9

If  3 or 6 and 9 are not included, then the digits remained = 0,1,2,4,5,7,8

i.e. 7 digits remained.

We assume that the repetition of digits is allowed.

By using  the fundamental counting principle , the number of 5 digit numbers  made by these 7 digits will be :-

$(7)^5=16807$

Hence, the number of 5 digit number which do not contain the digits 3 or 6 or 9=16807