CENTUM

https://drive.google.com/file/d/14bX-DUK4keD0va06iXkYGlOVh2mhUbp0/view?usp=sharing

the units place can have either 1,2 or 8

if the units digit has 1 or 2 there are only 3 different arrangements of the other places(because 8 is repeated)

if the units digit has 8 there are 6 different arrangements of the other places

6 8s in units place

3 1s in units place

3 2s in units place

6*8+3*1+3*2

57

the same can be said for digits of the other places as well

57*1000+57*100+57*10+57

62700+627

63327

answer is

Jahaan Kukreja’s answer:

https://drive.google.com/file/d/19AbTw8vOwfUynx_aQwQc08q6fkhasBCn/view?usp=sharing

Anirudh Seetharaman’s answer:

https://drive.google.com/file/d/1dSYLk3lcS2_2YvIW8Or-a9VugrrUG2d1/view?usp=sharing