Tom and Jerry disturbed each others' peace.Why it's wrong to use ''each others' '' here
Tom and Jerry=They
So plural subject,therefore ''each others' '' and not ''each other's ''

Question

Answer

Thank you Trina.

Answer

The word 'each' shows a single person/object or a group of people/things as a single unit. 
When we use 'each', we refer to someone or something ONE AT A TIME.
So, the word each always take an inflected verb form -s (takes, bakes) and the words is, has, and was.

"Each other's peace" refers to Tom's peace and Jerry's peace ONE AT A TIME.

Well, just remember that the word 'each' simply signals the next word to be in singular form. That's just the rule.