Please specify how many positive integers display the following features:
a. The number is below 10^12.
b. It is a multiple of 225.
c. Its decimal representation involves only two distinct digits.
Provide a justification of your result..
(In reply to
Analytic solution by Larry)
a. One word for your expose !
C H A P E A U !.
b. The source was somewhere in Putnam but it referred to ones and zeroes and was copied by Ravi Raja long time ago.
I found it more challenging to generalise.
c. BTW: Since my solution is isomorphic I will refer to yours as “official “
WHY NO ONE RATED THIS PUZZLE?
Edited on April 13, 2022, 4:48 am