I much preferred the attitude of one of my high school teachers:
“I will accept two answers to quiz question #5. Cynthia got a different answer from me. Knowing Cynthia’s work, I double checked my own reasoning and found that she was right and I was wrong. Of course, anyone who got her answer gets credit… but I will also give credit to those who had my original answer. Now I’ll explain what was wrong with ‘our’ reasoning.”
I much preferred the attitude of one of my high school teachers:
“I will accept two answers to quiz question #5. Cynthia got a different answer from me. Knowing Cynthia’s work, I double checked my own reasoning and found that she was right and I was wrong. Of course, anyone who got her answer gets credit… but I will also give credit to those who had my original answer. Now I’ll explain what was wrong with ‘our’ reasoning.”