Question

Q.6 How many numbers with two or more digits can be formed with the digits
1,2,3,4,5,6,7,8,9. so that in every such number, each digit is used at most once and the
digits appear in the ascending order?​

Answer 1

Correct Answer: 502

As the digits appear in ascending order in the numbers, number of ways of forming a n-digit number using the 9 digits =

9

C

n

Number of possible two-digit numbers which can be formed =

9

C

2

+

9

C

3

+

9

C

4

+

9

C

5

+

9

C

6

+

9

C

7

+

9

C

8

+

9

C

9

=

2

9

−

(

9

C

1

+

9

C

1

)

=

512

−

(

1

+

9

)

=

502

Answer 2

Answer:

Correct Answer is 502

Please mark as brainlist