Same with the Lusophon Mathematical Olympiad 2023 example.
It makes a bunch of specious claims about parity. (Adding 4 to a number changes the parity? Therefore, the parity of each colour always changes for each turn? Therefore, the parity will always be the same as it was initially?) And then it concludes that since the parity is right, 2022 of each colour must be a reachable state.
Which, as you say, is quite possible the correct answer, but it's really weird to put it out there as an example with no comment on the reasoning.
It makes a bunch of specious claims about parity. (Adding 4 to a number changes the parity? Therefore, the parity of each colour always changes for each turn? Therefore, the parity will always be the same as it was initially?) And then it concludes that since the parity is right, 2022 of each colour must be a reachable state.
Which, as you say, is quite possible the correct answer, but it's really weird to put it out there as an example with no comment on the reasoning.