Quant and LRDI queries | CAT 2018 | Breakspace

Clearing doubts of CAT 2018 aspirants, by IIMA and IIMC mentors of Breakspace

Question on Remainder:


Anil wrote down all the possible three-digit numbers with distinct digits on a blackboard. Of these numbers, Biswas erased all the numbers whose first and last digits were either both even or both odd. How many numbers were left on the board?