1. According to the short passage, Sam mistakenly sent an unrevised version of the purchase agreement. The unrevised version does not contain the convenant by Sam not to compete.
2. All of the other agreements contained in the purchase agreement except for the convenant not to compete is enforceable. This is because Sam has mistakenly sent a copy that does not contain the convenant as agreed by himself and Betty not to compete for a period of Ten years. Even if Betty files a lawsuit on breach of agreement, her case would lack substance as the accused never assented to her convenant.
3. Yes, Sam violated the convenant If the purchase agreement contained a convenant not to compete and he went ahead to work for his old clients regardless of whether the jobs were in town or not. This would be a breach of agreement and Sam may pay heavily for it if Betty takes it up as a subject for litigation.